Python * ** *args **kwargs用法與區別

*: 調用函數時，*用在tuple變量之前作爲函數參數，可將tuple/list 轉化爲多個參數傳入函數
**: 調用函數時，**用在字典變量之前作爲函數參數，可將字典 轉化爲多個關鍵字參數傳入函數
*args: 允許函數接收多個參數，函數體內args類型爲tuple
**kwargs: 允許函數接收多個關鍵字參數，函數體內kwargs爲字典

代碼例子

# -*- 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))

    # 調用函數時，**把字典轉爲多個關鍵字參數傳入函數
    person(**kwargs)

    # 調用函數時，*可以展開tuple爲多個參數傳入函數，所以len(tuple)應該等於函數參數個數，否則會報錯
    add_function(*args)


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

運行結果：

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