28.3. __builtin__
— Built-in objects¶
This module provides direct access to all ‘built-in’ identifiers of Python; for
example, __builtin__.open
is the full name for the built-in function
open()
. See 内置函数 and 内置常量 for
documentation.
This module is not normally accessed explicitly by most applications, but can be
useful in modules that provide objects with the same name as a built-in value,
but in which the built-in of that name is also needed. For example, in a module
that wants to implement an open()
function that wraps the built-in
open()
, this module can be used directly:
import __builtin__
def open(path):
f = __builtin__.open(path, 'r')
return UpperCaser(f)
class UpperCaser:
'''Wrapper around a file that converts output to upper-case.'''
def __init__(self, f):
self._f = f
def read(self, count=-1):
return self._f.read(count).upper()
# ...
CPython implementation detail: Most modules have the name __builtins__
(note the 's'
) made available
as part of their globals. The value of __builtins__
is normally either
this module or the value of this modules’s __dict__
attribute. Since
this is an implementation detail, it may not be used by alternate
implementations of Python.