python函数参数之_可变参数

python函数之_可变参数

两种格式:
    1.一星: 被初始化为元组,接收位置剩余的参数      --- 默认值是空元组()
    2.两星: 被初始化为有序字典,接收剩余的关键字参数 --- 默认值是空字典{}
    3.Note: 一星必须在两星之前

1.Any formal parameters which occur after the *args parameter are ‘keyword-only’ arguments,meaning that they can only be used as keywords rather than positional arguments.

备注:‘keyword-only’ arguments是什么鬼?

def f(*a, b = 8):    print(a, b)f(3,  4)输出:    (3, 4) 8

def f(*a, b):    print(a, b)f(3,  b = 4)输出:    (3,) 4

2.一星必须在两星之前

def f(a, *b, **c):    print(a)    print(b)    print(c)f(2, 3, 4, x = 5, y = 6)输出:    2    (3, 4)    {'x': 5, 'y': 6}