python传递任意数量的实参

1、传递任意的实参

def make(*test):#带*号
    print(test)
make("one")#传递一个实参
make("one","two")#传递两个实参

2、传递任意数的关键字参数

def test(first,last,**user):#关键字参数两个*号、后面user中像字典
    profile = {}
    profile["first_name"] = first
    profile["last_name"] = last
    for key,value in user.items():
        profile[key] = value
    return profile

duibi = test("add","achengqian",
              bd="boy",#关键字参数中间是“=”,与字典有出入，并且bd没有带引号
              cd="can")
print(duibi)

 

*args是可变参数，args接收的是一个tuple；

**kw是关键字参数，kw接收的是一个dict。

def f1(a, b, c=0, *args, **kw):
    print('a =', a, 'b =', b, 'c =', c, 'args =', args, 'kw =', kw)

def f2(a, b, c=0, *, d, **kw):
    print('a =', a, 'b =', b, 'c =', c, 'd =', d, 'kw =', kw)

在函数调用的时候，Python解释器自动按照参数位置和参数名把对应的参数传进去。

>>> f1(1, 2)
a = 1 b = 2 c = 0 args = () kw = {}
>>> f1(1, 2, c=3)
a = 1 b = 2 c = 3 args = () kw = {}
>>> f1(1, 2, 3, 'a', 'b')
a = 1 b = 2 c = 3 args = ('a', 'b') kw = {}
>>> f1(1, 2, 3, 'a', 'b', x=99)
a = 1 b = 2 c = 3 args = ('a', 'b') kw = {'x': 99}
>>> f2(1, 2, d=99, ext=None)
a = 1 b = 2 c = 0 d = 99 kw = {'ext': None}


4、lambda函数的格式
sum = lambda a,b:a+b