python内置方法、模块讲解（八）

• 2016-03-04 23:16:07
• 1103
• 0

• python
• authen

二十五、execfile方法

1、定义：

execfile(...)
    execfile(filename[, globals[, locals]])

    Read and execute a Python script from a file.
    The globals and locals are dictionaries, defaulting to the current
    globals and locals.  If only globals is given, locals defaults to it.

2、解释：从一个文件中读取并执行一个python脚本，默认取当前的全局变量和局部变量

3、举例：（略）

二十六、exit方法

此方法用处较少我一般只用于退出python运行环境

二十七、file类

1、定义：

class file(object)
 |  file(name[, mode[, buffering]]) -> file object
 |
 |  Open a file.  The mode can be 'r', 'w' or 'a' for reading (default),
 |  writing or appending.  The file will be created if it doesn't exist
 |  when opened for writing or appending; it will be truncated when
 |  opened for writing.  Add a 'b' to the mode for binary files.
 |  Add a '+' to the mode to allow simultaneous reading and writing.
 |  If the buffering argument is given, 0 means unbuffered, 1 means line
 |  buffered, and larger numbers specify the buffer size.  The preferred way
 |  to open a file is with the builtin open() function.
 |  Add a 'U' to mode to open the file for input with universal newline
 |  support.  Any line ending in the input file will be seen as a '\n'
 |  in Python.  Also, a file so opened gains the attribute 'newlines';
 |  the value for this attribute is one of None (no newline read yet),
 |  '\r', '\n', '\r\n' or a tuple containing all the newline types seen.
 |
 |  'U' cannot be combined with 'w' or '+' mode.

2、解释：打开一个文件并返回一个文件对象，一般我们用open 方法

3、举例：

>>> a = file(r'G:\wk\myblog\1\builtins\compile.py')
>>> dir(a)
['__class__', '__delattr__', '__doc__', '__enter__', '__exit__', '__format__', '__getattribute__', '__hash__', '__init__', '__iter__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', 'close', 'closed', 'encoding', 'errors', 'fileno', 'flush', 'isatty', 'mode', 'name', 'newlines', 'next', 'read', 'readinto', 'readline', 'readlines', 'seek', 'softspace', 'tell', 'truncate', 'write', 'writelines', 'xreadlines']
>>> b = open(r'G:\wk\myblog\1\builtins\compile.py')
>>> dir(b)
['__class__', '__delattr__', '__doc__', '__enter__', '__exit__', '__format__', '__getattribute__', '__hash__', '__init__', '__iter__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', 'close', 'closed', 'encoding', 'errors', 'fileno', 'flush', 'isatty', 'mode', 'name', 'newlines', 'next', 'read', 'readinto', 'readline', 'readlines', 'seek', 'softspace', 'tell', 'truncate', 'write', 'writelines', 'xreadlines']

注：可以看出file与open是一样的