[python][oldboy] * **的用法

* 和**主要用在函数的参数中，

# coding=utf8

"""
三种编码：
    1 python程序代码的编码
        # coding=utf8
    2 设置/查看python程序运行环境的编码
        import sys
        查看
        sys.getdefaultencoding()
        设置
        reload(sys)
        sys.setdefaultencoding('utf-8')
    3 python程序读取外部文件，网页内容的编码
        encode,decode
"""

def function(*args, **kwargs):
    """
     :param args: 表示任何多个无名参数，这些参数会以一个tupe的形式访问
    :param kwargs: 用来处理任意个有名字的参数，这些参数用dict来访问
    :return:
    """
    print "args type = %s" % type(args)
    print "args = %s" % str(args)
    for i, item in enumerate(args):
        print "args[%d] = %s" % (i, item)

    print "------------"
    print "kwargs type = %s" % type(kwargs)
    print "kwargs = %s" % kwargs
    for k, v in kwargs.items():
        print "%s:%s" % (k, v)


function(1, 2, 3, name="liuzhipeng", sex="male")

结果为

C:Python27python.exe C:/Users/Administrator/PycharmProjects/oldboy/lesson_3/44.py
args type = <type 'tuple'>
args = (1, 2, 3)
args[0] = 1
args[1] = 2
args[2] = 3
------------
kwargs type = <type 'dict'>
kwargs = {'name': 'liuzhipeng', 'sex': 'male'}
name:liuzhipeng
sex:male

Process finished with exit code 0

* 和** 在打印元组（列表）和字典的时候很有用

print "i am {name}, and age is {age}".format(**{"name": "lzp", "age": 14})
print "i am {}, and age is {}".format(*("lzp",14))

i am lzp, and age is 14
i am lzp, and age is 14