python文件操作：

open函数，该函数用于文件处理

操作文件时，一般需要经历如下步骤：

• 打开文件
• 操作文件

一、打开文件

打开文件时，需要指定文件路径和以何等方式打开文件，打开后，即可获取该文件句柄，日后通过此文件句柄对该文件操作。

打开文件的模式有：

• r，只读模式（默认）。
• w，只写模式。【不可读；不存在则创建；存在则删除内容；】
• a，追加模式。【可读；   不存在则创建；存在则只追加内容；】

"+" 表示可以同时读写某个文件

• r+，可读写文件。【可读；可写；可追加】
• w+，写读
• a+，同a

"U"表示在读取时，可以将 \r \n \r\n自动转换成 \n （与 r 或 r+ 模式同使用）

• rU
• r+U

"b"表示处理二进制文件（如：FTP发送上传ISO镜像文件，linux可忽略，windows处理二进制文件时需标注）

• rb
• wb
• ab
• 二、操作
• Python 2.x

  

  

  class TextIOWrapper(_TextIOBase):
      """
      Character and line based layer over a BufferedIOBase object, buffer.
  
      encoding gives the name of the encoding that the stream will be
      decoded or encoded with. It defaults to locale.getpreferredencoding(False).
  
      errors determines the strictness of encoding and decoding (see
      help(codecs.Codec) or the documentation for codecs.register) and
      defaults to "strict".
  
      newline controls how line endings are handled. It can be None, ‘‘,
      ‘\n‘, ‘\r‘, and ‘\r\n‘.  It works as follows:
  
      * On input, if newline is None, universal newlines mode is
        enabled. Lines in the input can end in ‘\n‘, ‘\r‘, or ‘\r\n‘, and
        these are translated into ‘\n‘ before being returned to the
        caller. If it is ‘‘, universal newline mode is enabled, but line
        endings are returned to the caller untranslated. If it has any of
        the other legal values, input lines are only terminated by the given
        string, and the line ending is returned to the caller untranslated.
  
      * On output, if newline is None, any ‘\n‘ characters written are
        translated to the system default line separator, os.linesep. If
        newline is ‘‘ or ‘\n‘, no translation takes place. If newline is any
        of the other legal values, any ‘\n‘ characters written are translated
        to the given string.
  
      If line_buffering is True, a call to flush is implied when a call to
      write contains a newline character.
      """
      def close(self, *args, **kwargs): # real signature unknown
          关闭文件
          pass
  
      def fileno(self, *args, **kwargs): # real signature unknown
          文件描述符
          pass
  
      def flush(self, *args, **kwargs): # real signature unknown
          刷新文件内部缓冲区
          pass
  
      def isatty(self, *args, **kwargs): # real signature unknown
          判断文件是否是同意tty设备
          pass
  
      def read(self, *args, **kwargs): # real signature unknown
          读取指定字节数据
          pass
  
      def readable(self, *args, **kwargs): # real signature unknown
          是否可读
          pass
  
      def readline(self, *args, **kwargs): # real signature unknown
          仅读取一行数据
          pass
  
      def seek(self, *args, **kwargs): # real signature unknown
          指定文件中指针位置
          pass
  
      def seekable(self, *args, **kwargs): # real signature unknown
          指针是否可操作
          pass
  
      def tell(self, *args, **kwargs): # real signature unknown
          获取指针位置
          pass
  
      def truncate(self, *args, **kwargs): # real signature unknown
          截断数据，仅保留指定之前数据
          pass
  
      def writable(self, *args, **kwargs): # real signature unknown
          是否可写
          pass
  
      def write(self, *args, **kwargs): # real signature unknown
          写内容
          pass
  
      def __getstate__(self, *args, **kwargs): # real signature unknown
          pass
  
      def __init__(self, *args, **kwargs): # real signature unknown
          pass
  
      @staticmethod # known case of __new__
      def __new__(*args, **kwargs): # real signature unknown
          """ Create and return a new object.  See help(type) for accurate signature. """
          pass
  
      def __next__(self, *args, **kwargs): # real signature unknown
          """ Implement next(self). """
          pass
  
      def __repr__(self, *args, **kwargs): # real signature unknown
          """ Return repr(self). """
          pass
  
      buffer = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default
  
      closed = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default
  
      encoding = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default
  
      errors = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default
  
      line_buffering = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default
  
      name = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default
  
      newlines = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default
  
      _CHUNK_SIZE = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default
  
      _finalizing = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default