pprint — 예쁜 데이터 인쇄기

소스 코드: Lib/pprint.py


pprint 모듈은 임의의 파이썬 데이터 구조를 인터프리터의 입력으로 사용할 수 있는 형태로 “예쁘게 인쇄”할 수 있는 기능을 제공합니다. 포맷된 구조에 기본 파이썬 형이 아닌 객체가 포함되면, 표현은 로드되지 않을 수 있습니다. 파일, 소켓 또는 클래스와 같은 객체뿐만 아니라 파이썬 리터럴로 표현할 수 없는 다른 많은 객체가 포함된 경우입니다.

The formatted representation keeps objects on a single line if it can, and breaks them onto multiple lines if they don’t fit within the allowed width, adjustable by the width parameter defaulting to 80 characters.

딕셔너리는 디스플레이를 계산하기 전에 키로 정렬됩니다.

버전 3.9에서 변경: types.SimpleNamespace를 예쁘게 인쇄하는 지원이 추가되었습니다.

버전 3.10에서 변경: Added support for pretty-printing dataclasses.dataclass.

Functions

pprint.pp(object, *args, sort_dicts=False, **kwargs)

Prints the formatted representation of object followed by a newline. If sort_dicts is false (the default), dictionaries will be displayed with their keys in insertion order, otherwise the dict keys will be sorted. args and kwargs will be passed to pprint() as formatting parameters.

>>> import pprint
>>> stuff = ['spam', 'eggs', 'lumberjack', 'knights', 'ni']
>>> stuff.insert(0, stuff)
>>> pprint.pp(stuff)
[<Recursion on list with id=...>,
 'spam',
 'eggs',
 'lumberjack',
 'knights',
 'ni']

Added in version 3.8.

pprint.pprint(object, stream=None, indent=1, width=80, depth=None, *, compact=False, sort_dicts=True, underscore_numbers=False)

Prints the formatted representation of object on stream, followed by a newline. If stream is None, sys.stdout is used. This may be used in the interactive interpreter instead of the print() function for inspecting values (you can even reassign print = pprint.pprint for use within a scope).

The configuration parameters stream, indent, width, depth, compact, sort_dicts and underscore_numbers are passed to the PrettyPrinter constructor and their meanings are as described in its documentation below.

Note that sort_dicts is True by default and you might want to use pp() instead where it is False by default.

pprint.pformat(object, indent=1, width=80, depth=None, *, compact=False, sort_dicts=True, underscore_numbers=False)

Return the formatted representation of object as a string. indent, width, depth, compact, sort_dicts and underscore_numbers are passed to the PrettyPrinter constructor as formatting parameters and their meanings are as described in its documentation below.

pprint.isreadable(object)

object의 포맷된 표현이 “읽을 수 있는”지, 즉 eval()을 사용하여 값을 재구성하는 데 사용할 수 있는지 판단합니다. 재귀적 객체에 대해서는 항상 False를 반환합니다.

>>> pprint.isreadable(stuff)
False
pprint.isrecursive(object)

Determine if object requires a recursive representation. This function is subject to the same limitations as noted in saferepr() below and may raise an RecursionError if it fails to detect a recursive object.

pprint.saferepr(object)

Return a string representation of object, protected against recursion in some common data structures, namely instances of dict, list and tuple or subclasses whose __repr__ has not been overridden. If the representation of object exposes a recursive entry, the recursive reference will be represented as <Recursion on typename with id=number>. The representation is not otherwise formatted.

>>> pprint.saferepr(stuff)
"[<Recursion on list with id=...>, 'spam', 'eggs', 'lumberjack', 'knights', 'ni']"

PrettyPrinter 객체

This module defines one class:

class pprint.PrettyPrinter(indent=1, width=80, depth=None, stream=None, *, compact=False, sort_dicts=True, underscore_numbers=False)

Construct a PrettyPrinter instance. This constructor understands several keyword parameters.

stream (default sys.stdout) is a file-like object to which the output will be written by calling its write() method. If both stream and sys.stdout are None, then pprint() silently returns.

Other values configure the manner in which nesting of complex data structures is displayed.

indent (default 1) specifies the amount of indentation added for each nesting level.

depth controls the number of nesting levels which may be printed; if the data structure being printed is too deep, the next contained level is replaced by .... By default, there is no constraint on the depth of the objects being formatted.

width (default 80) specifies the desired maximum number of characters per line in the output. If a structure cannot be formatted within the width constraint, a best effort will be made.

compact impacts the way that long sequences (lists, tuples, sets, etc) are formatted. If compact is false (the default) then each item of a sequence will be formatted on a separate line. If compact is true, as many items as will fit within the width will be formatted on each output line.

If sort_dicts is true (the default), dictionaries will be formatted with their keys sorted, otherwise they will display in insertion order.

If underscore_numbers is true, integers will be formatted with the _ character for a thousands separator, otherwise underscores are not displayed (the default).

버전 3.4에서 변경: compact 매개 변수가 추가되었습니다.

버전 3.8에서 변경: sort_dicts 매개 변수가 추가되었습니다.

버전 3.10에서 변경: Added the underscore_numbers parameter.

버전 3.11에서 변경: No longer attempts to write to sys.stdout if it is None.

>>> import pprint
>>> stuff = ['spam', 'eggs', 'lumberjack', 'knights', 'ni']
>>> stuff.insert(0, stuff[:])
>>> pp = pprint.PrettyPrinter(indent=4)
>>> pp.pprint(stuff)
[   ['spam', 'eggs', 'lumberjack', 'knights', 'ni'],
    'spam',
    'eggs',
    'lumberjack',
    'knights',
    'ni']
>>> pp = pprint.PrettyPrinter(width=41, compact=True)
>>> pp.pprint(stuff)
[['spam', 'eggs', 'lumberjack',
  'knights', 'ni'],
 'spam', 'eggs', 'lumberjack', 'knights',
 'ni']
>>> tup = ('spam', ('eggs', ('lumberjack', ('knights', ('ni', ('dead',
... ('parrot', ('fresh fruit',))))))))
>>> pp = pprint.PrettyPrinter(depth=6)
>>> pp.pprint(tup)
('spam', ('eggs', ('lumberjack', ('knights', ('ni', ('dead', (...)))))))

PrettyPrinter 인스턴스에는 다음과 같은 메서드가 있습니다:

PrettyPrinter.pformat(object)

object의 포맷된 표현을 반환합니다. PrettyPrinter 생성자에 전달된 옵션을 고려합니다.

PrettyPrinter.pprint(object)

구성된 스트림에 object의 포맷된 표현과 불 넘김을 인쇄합니다.

다음 메서드는 같은 이름의 해당 함수에 대한 구현을 제공합니다. 새로운 PrettyPrinter 객체를 만들 필요가 없으므로, 인스턴스에서 이러한 메서드를 사용하는 것이 약간 더 효율적입니다.

PrettyPrinter.isreadable(object)

object의 포맷된 표현이 “읽을 수 있는”지, 즉 eval()을 사용하여 값을 재구성하는 데 사용할 수 있는지 판단합니다. 재귀 객체에 대해 False를 반환함에 유의하십시오. PrettyPrinterdepth 매개 변수가 설정되고 객체가 허용된 것보다 더 깊으면, False를 반환합니다.

PrettyPrinter.isrecursive(object)

object가 재귀적 표현을 요구하는지 판단합니다.

이 메서드는 서브 클래스가 객체가 문자열로 변환되는 방식을 수정할 수 있도록 하는 훅으로 제공됩니다. 기본 구현은 saferepr() 구현의 내부를 사용합니다.

PrettyPrinter.format(object, context, maxlevels, level)

세 가지 값을 반환합니다: 포맷된 버전의 object를 문자열로, 결과가 읽을 수 있는지를 나타내는 플래그와 재귀가 감지되었는지를 나타내는 플래그. 첫 번째 인자는 표시할 객체입니다. 두 번째는 현재 표현 컨텍스트(표현에 영향을 주는 object의 직접 및 간접 컨테이너)의 일부인 객체의 id()를 키로 포함하는 딕셔너리입니다; 이미 context에 표현된 객체가 표현되어야 할 필요가 있으면, 세 번째 반환 값은 True이어야 합니다. format() 메서드에 대한 재귀 호출은 컨테이너에 대한 추가 항목을 이 딕셔너리에 추가해야 합니다. 세 번째 인자 maxlevels는 재귀에 요청된 제한을 줍니다; 요청된 제한이 없으면 0입니다. 이 인자는 재귀 호출에 수정되지 않은 채 전달되어야 합니다. 네 번째 인자 level은 현재 수준을 제공합니다; 재귀 호출은 현재 호출보다 작은 값으로 전달되어야 합니다.

예제

To demonstrate several uses of the pp() function and its parameters, let’s fetch information about a project from PyPI:

>>> import json
>>> import pprint
>>> from urllib.request import urlopen
>>> with urlopen('https://pypi.org/pypi/sampleproject/json') as resp:
...     project_info = json.load(resp)['info']

In its basic form, pp() shows the whole object:

>>> pprint.pp(project_info)
{'author': 'The Python Packaging Authority',
 'author_email': 'pypa-dev@googlegroups.com',
 'bugtrack_url': None,
 'classifiers': ['Development Status :: 3 - Alpha',
                 'Intended Audience :: Developers',
                 'License :: OSI Approved :: MIT License',
                 'Programming Language :: Python :: 2',
                 'Programming Language :: Python :: 2.6',
                 'Programming Language :: Python :: 2.7',
                 'Programming Language :: Python :: 3',
                 'Programming Language :: Python :: 3.2',
                 'Programming Language :: Python :: 3.3',
                 'Programming Language :: Python :: 3.4',
                 'Topic :: Software Development :: Build Tools'],
 'description': 'A sample Python project\n'
                '=======================\n'
                '\n'
                'This is the description file for the project.\n'
                '\n'
                'The file should use UTF-8 encoding and be written using '
                'ReStructured Text. It\n'
                'will be used to generate the project webpage on PyPI, and '
                'should be written for\n'
                'that purpose.\n'
                '\n'
                'Typical contents for this file would include an overview of '
                'the project, basic\n'
                'usage examples, etc. Generally, including the project '
                'changelog in here is not\n'
                'a good idea, although a simple "What\'s New" section for the '
                'most recent version\n'
                'may be appropriate.',
 'description_content_type': None,
 'docs_url': None,
 'download_url': 'UNKNOWN',
 'downloads': {'last_day': -1, 'last_month': -1, 'last_week': -1},
 'home_page': 'https://github.com/pypa/sampleproject',
 'keywords': 'sample setuptools development',
 'license': 'MIT',
 'maintainer': None,
 'maintainer_email': None,
 'name': 'sampleproject',
 'package_url': 'https://pypi.org/project/sampleproject/',
 'platform': 'UNKNOWN',
 'project_url': 'https://pypi.org/project/sampleproject/',
 'project_urls': {'Download': 'UNKNOWN',
                  'Homepage': 'https://github.com/pypa/sampleproject'},
 'release_url': 'https://pypi.org/project/sampleproject/1.2.0/',
 'requires_dist': None,
 'requires_python': None,
 'summary': 'A sample Python project',
 'version': '1.2.0'}

결과는 특정 depth로 제한될 수 있습니다 (더 깊은 내용에는 줄임표가 사용됩니다):

>>> pprint.pp(project_info, depth=1)
{'author': 'The Python Packaging Authority',
 'author_email': 'pypa-dev@googlegroups.com',
 'bugtrack_url': None,
 'classifiers': [...],
 'description': 'A sample Python project\n'
                '=======================\n'
                '\n'
                'This is the description file for the project.\n'
                '\n'
                'The file should use UTF-8 encoding and be written using '
                'ReStructured Text. It\n'
                'will be used to generate the project webpage on PyPI, and '
                'should be written for\n'
                'that purpose.\n'
                '\n'
                'Typical contents for this file would include an overview of '
                'the project, basic\n'
                'usage examples, etc. Generally, including the project '
                'changelog in here is not\n'
                'a good idea, although a simple "What\'s New" section for the '
                'most recent version\n'
                'may be appropriate.',
 'description_content_type': None,
 'docs_url': None,
 'download_url': 'UNKNOWN',
 'downloads': {...},
 'home_page': 'https://github.com/pypa/sampleproject',
 'keywords': 'sample setuptools development',
 'license': 'MIT',
 'maintainer': None,
 'maintainer_email': None,
 'name': 'sampleproject',
 'package_url': 'https://pypi.org/project/sampleproject/',
 'platform': 'UNKNOWN',
 'project_url': 'https://pypi.org/project/sampleproject/',
 'project_urls': {...},
 'release_url': 'https://pypi.org/project/sampleproject/1.2.0/',
 'requires_dist': None,
 'requires_python': None,
 'summary': 'A sample Python project',
 'version': '1.2.0'}

또한, 최대 문자 width를 제안할 수 있습니다. 긴 객체를 분할 할 수 없으면, 지정된 너비를 초과합니다:

>>> pprint.pp(project_info, depth=1, width=60)
{'author': 'The Python Packaging Authority',
 'author_email': 'pypa-dev@googlegroups.com',
 'bugtrack_url': None,
 'classifiers': [...],
 'description': 'A sample Python project\n'
                '=======================\n'
                '\n'
                'This is the description file for the '
                'project.\n'
                '\n'
                'The file should use UTF-8 encoding and be '
                'written using ReStructured Text. It\n'
                'will be used to generate the project '
                'webpage on PyPI, and should be written '
                'for\n'
                'that purpose.\n'
                '\n'
                'Typical contents for this file would '
                'include an overview of the project, '
                'basic\n'
                'usage examples, etc. Generally, including '
                'the project changelog in here is not\n'
                'a good idea, although a simple "What\'s '
                'New" section for the most recent version\n'
                'may be appropriate.',
 'description_content_type': None,
 'docs_url': None,
 'download_url': 'UNKNOWN',
 'downloads': {...},
 'home_page': 'https://github.com/pypa/sampleproject',
 'keywords': 'sample setuptools development',
 'license': 'MIT',
 'maintainer': None,
 'maintainer_email': None,
 'name': 'sampleproject',
 'package_url': 'https://pypi.org/project/sampleproject/',
 'platform': 'UNKNOWN',
 'project_url': 'https://pypi.org/project/sampleproject/',
 'project_urls': {...},
 'release_url': 'https://pypi.org/project/sampleproject/1.2.0/',
 'requires_dist': None,
 'requires_python': None,
 'summary': 'A sample Python project',
 'version': '1.2.0'}