python中的*args和**kwargs

通过小例子介绍args和*kwargs的功能

example1

def test(a,*args):
    print(a)
    print(args)

test(1,2,3,4)
------------------------------------
1
(2, 3, 4)

example2

def test(a,*args,**kwargs):
    print(a)
    print(args)
    print(kwargs)

test(1,2,3,4)
------------------------------------
1
(2, 3, 4)
{}

example3

def test(a,*args,**kwargs):
    print(a)
    print(args)
    print(kwargs)

test(1,2,3,4,b=10, c=6, d=7)
------------------------------------
1
(2, 3, 4)
{'b': 10, 'c': 6, 'd': 7}

kwargs.get（arg1,value）:用于得到kwargs中arg1的值，如果kwargs未给出该值，那就得到value

example4

def test(a,*args,**kwargs):
    print(a)
    print(args)
    print(kwargs)
    x=kwargs.get('b',100)
    print(x)
test(1,2,3,4,b=5, c=6, d=7)
------------------------------------
1
(2, 3, 4)
{'b': 5, 'c': 6, 'd': 7}
5

example5

def test(a,*args,**kwargs):
    print(a)
    print(args)
    print(kwargs)
    x=kwargs.get('e',100)
    print(x)
test(1,2,3,4,b=5, c=6, d=7)
------------------------------------
1
(2, 3, 4)
{'b': 10, 'c': 6, 'd': 7}
100