Python * ** *args **kwargs用法与区别

*: 调用函数时，*用在tuple变量之前作为函数参数，可将tuple/list 转化为多个参数传入函数
**: 调用函数时，**用在字典变量之前作为函数参数，可将字典 转化为多个关键字参数传入函数
*args: 允许函数接收多个参数，函数体内args类型为tuple
**kwargs: 允许函数接收多个关键字参数，函数体内kwargs为字典

代码例子

# -*- coding: utf-8 -*-
"""
 * explain how * ** *args **kwargs work
"""


def add_function(a, b):
    print("{}+{}={}".format(a, b, a+b))


def person(name=None, age=10):
    print("Person name: {}; age: {}".format(name, age))


def show_params(first, second, *args, **kwargs):
    """
    show how parameters work
    Args:
        first:
        second:
        *args: accept any number argument
        **kwargs: accept any number key-value argument

    Returns:

    """

    print("first param is {}".format(first))
    print("second param is {}".format(second))
    print("args is a tuple {}".format(args))
    print("kwargs is a dictionary {}".format(kwargs))

    # 调用函数时，**把字典转为多个关键字参数传入函数
    person(**kwargs)

    # 调用函数时，*可以展开tuple为多个参数传入函数，所以len(tuple)应该等于函数参数个数，否则会报错
    add_function(*args)


if __name__ == '__main__':
    show_params(1, 2, 3, 4, name="dongsheng", age=25)

运行结果：

first param is 1
second param is 2
args is a tuple (3, 4)
kwargs is a dictionary {‘name’: ‘dongsheng’, ‘age’: 25}
Person name: dongsheng; age: 25
3+4=7