python内置方法、模块讲解（十八）

• 2016-05-01 17:55:27
• 1435
• 0

• python
• authen

四十七、list类

1、定义：

class list(object)
 |  list() -> new empty list
 |  list(iterable) -> new list initialized from iterable's items

2、解释：生成一个list 对象或者将一个迭代对象的所有迭代元素初始化为一个list对象。

另外list对象本身还有很多对应的方法，可以使用前面说的dir函数进行查看，这里不做介绍有机会后面会讲解：

>>> dir(list())
['__add__', '__class__', '__contains__', '__delattr__', '__delitem__', '__delslice__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__getslice__', '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__iter__', '__le__', '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__reversed__', '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__sizeof__', '__str__', '__subclasshook__', 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove', 'reverse', 'sort']

3、举例：

>>> list('123asdfas')
['1', '2', '3', 'a', 's', 'd', 'f', 'a', 's']
>>> list((1,2,4,'a'))
[1, 2, 4, 'a']
>>> list()
[]

四十八、locals方法

1、定义：

locals(...)
    locals() -> dictionary

    Update and return a dictionary containing the current scope's local variables.

2、解释：更新并返回包含当前程序概念作用域的本地变量

3、举例：

>>> locals()
{'__builtins__': <module '__builtin__' (built-in)>, '__name__': '__main__', '__doc__': None, '__package__': None}
>>> import datetime
>>> locals()
{'__builtins__': <module '__builtin__' (built-in)>, '__name__': '__main__', 'datetime': <module 'datetime' (built-in)>, '__doc__': None, '__package__': None}

四十九、long类

1、定义：

class long(object)
 |  long(x=0) -> long
 |  long(x, base=10) -> long
 |
 |  Convert a number or string to a long integer, or return 0L if no arguments
 |  are given.  If x is floating point, the conversion truncates towards zero.
 |
 |  If x is not a number or if base is given, then x must be a string or
 |  Unicode object representing an integer literal in the given base.  The
 |  literal can be preceded by '+' or '-' and be surrounded by whitespace.
 |  The base defaults to 10.  Valid bases are 0 and 2-36.  Base 0 means to
 |  interpret the base from the string as an integer literal.
 |  >>> int('0b100', base=0)
 |  4L

2、解释：该用法与int类似， 详见：http://aoyanming.com/blog/display/22

3、举例： 详见：http://aoyanming.com/blog/display/22