[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:\Python27\python.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