*args和**kwargs

*args和**kwargs主要用于函数定义,可以将不定量的参数传给一个函数

(ps:不是必须写成*args和**kwargs,只有变量前面的*[星号]才是必须的,也可以写成*var和**vars,*args和**kwargs只是一个通俗的定义)

以下来介绍这俩

1.*args的用法

  *args是用来发送一个非键值对的可变数量的参数列表给一个函数。举例如下

#/usr/bin/python
def test_args(argv1,*args):
    print "first arg is " + argv1
    for arg in args:
	print "another arg is " +  arg

test_args("first","python","nodejs")

  执行结果如下:

first arg is first
another arg is python
another arg is nodejs

2.**kwargs的用法

  **kwargs是用来将不定长度的键值对作为参数传给一个函数。举例如下:

#!/usr/bin/python
def test_kwargs(**kwargs):
    for key ,value in kwargs.items():
	print key + " is " + value
test_kwargs(name="zhaolibin",age="18")

  执行结果如下:

age is 18
name is zhaolibin

3.假如你要同时传入上述两种参数,则需要用以下顺序

  some_func(fargs, *args, **kwargs)   举例如下:

#!/usr/bin/python
def test_kwargs(farg,*argvs,**kwargs):
    print "farg is " + farg
    for arg in argvs:
	print "another arg is " +  arg
    for key ,value in kwargs.items():
	print key + " is " + value
test_kwargs("first","second","third",name="zhaolibin",age="18")

  执行结果如下:

farg is first
another arg is second
another arg is third
age is 18
name is zhaolibin

  

原文地址:https://www.cnblogs.com/creazylinux/p/7054340.html