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Python模块包中__init__.py文件的作用

分类: 文章 • 2024-09-15 14:14:34

在新建python包的时候，它默认生成了一个 __init__.py 的空文件。

Python模块包中__init__.py文件的作用

打开一看结果是空的，便觉得没有什么用，就把它删掉了。

Python模块包中__init__.py文件的作用

但是那个python包结果变成了Python文件夹了。

这是怎么回事呢！

原来在python模块的每一个包中，都有一个__init__.py文件（这个文件定义了包的属性和方法）然后是一些模块文件和子目录，假如子目录中也有 __init__.py 那么它就是这个包的子包了。当你将一个包作为模块导入（比如从 xml 导入 dom ）的时候，实际上导入了它的 __init__.py 文件。一个包是一个带有特殊文件 __init__.py 的目录。__init__.py 文件定义了包的属性和方法。其实它可以什么也不定义；可以只是一个空文件，但是必须存在。如果 __init__.py 不存在，这个目录就仅仅是一个目录，而不是一个包，它就不能被导入或者包含其它的模块和嵌套包。

__init__.py文件

这下面是我复制 io.py 里面的内容

"""该Py文件的简单介绍
The io module provides the Python interfaces to stream handling. The
builtin open function is defined in this module.

At the top of the I/O hierarchy is the abstract base class IOBase. It
defines the basic interface to a stream. Note, however, that there is no
separation between reading and writing to streams; implementations are
allowed to raise an OSError if they do not support a given operation.

Extending IOBase is RawIOBase which deals simply with the reading and
writing of raw bytes to a stream. FileIO subclasses RawIOBase to provide
an interface to OS files.

BufferedIOBase deals with buffering on a raw byte stream (RawIOBase). Its
subclasses, BufferedWriter, BufferedReader, and BufferedRWPair buffer
streams that are readable, writable, and both respectively.
BufferedRandom provides a buffered interface to random access
streams. BytesIO is a simple stream of in-memory bytes.

Another IOBase subclass, TextIOBase, deals with the encoding and decoding
of streams into text. TextIOWrapper, which extends it, is a buffered text
interface to a buffered raw stream (`BufferedIOBase`). Finally, StringIO
is an in-memory stream for text.

Argument names are not part of the specification, and only the arguments
of open() are intended to be used as keyword arguments.

data:

DEFAULT_BUFFER_SIZE

   An int containing the default buffer size used by the module's buffered
   I/O classes. open() uses the file's blksize (as obtained by os.stat) if
   possible.
"""
# New I/O library conforming to PEP 3116.
#作者信息modul

__author__ = ("Guido van Rossum <[email protected]>, "
              "Mike Verdone <[email protected]>, "
              "Mark Russell <[email protected]>, "
              "Antoine Pitrou <[email protected]>, "
              "Amaury Forgeot d'Arc <[email protected]>, "
              "Benjamin Peterson <[email protected]>")
#导入所有的模块

__all__ = ["BlockingIOError", "open", "IOBase", "RawIOBase", "FileIO",
           "BytesIO", "StringIO", "BufferedIOBase",
           "BufferedReader", "BufferedWriter", "BufferedRWPair",
           "BufferedRandom", "TextIOBase", "TextIOWrapper",
           "UnsupportedOperation", "SEEK_SET", "SEEK_CUR", "SEEK_END"]

#模块
import _io
import abc


#以下的事具体的配置过程，不详

from _io import (DEFAULT_BUFFER_SIZE, BlockingIOError, UnsupportedOperation,
                 open, FileIO, BytesIO, StringIO, BufferedReader,
                 BufferedWriter, BufferedRWPair, BufferedRandom,
                 IncrementalNewlineDecoder, TextIOWrapper)

OpenWrapper = _io.open # for compatibility with _pyio

# Pretend this exception was created here.
UnsupportedOperation.__module__ = "io"

# for seek()
SEEK_SET = 0
SEEK_CUR = 1
SEEK_END = 2

# Declaring ABCs in C is tricky so we do it here.
# Method descriptions and default implementations are inherited from the C
# version however.
class IOBase(_io._IOBase, metaclass=abc.ABCMeta):
    __doc__ = _io._IOBase.__doc__

class RawIOBase(_io._RawIOBase, IOBase):
    __doc__ = _io._RawIOBase.__doc__

class BufferedIOBase(_io._BufferedIOBase, IOBase):
    __doc__ = _io._BufferedIOBase.__doc__

class TextIOBase(_io._TextIOBase, IOBase):
    __doc__ = _io._TextIOBase.__doc__

RawIOBase.register(FileIO)

for klass in (BytesIO, BufferedReader, BufferedWriter, BufferedRandom,
              BufferedRWPair):
    BufferedIOBase.register(klass)

for klass in (StringIO, TextIOWrapper):
    TextIOBase.register(klass)
del klass

try:
    from _io import _WindowsConsoleIO
except ImportError:
    pass
else:
    RawIOBase.register(_WindowsConsoleIO)






















































































































































这下面是我复制 io.py 里面的内容





__all__
from  io import *  #导入所有的模块



															

																					

								

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