当你不确定你的函数里将要传递多少参数时你可以用*args, 它可以传递任意数量的参数。
**kwargs允许你使用没有事先定义的参数名。
- *arg 会把多出来的位置参数转化为 tuple
- **kwarg 会把关键字参数转化为 dict
*args和**kwargs可以同时在函数的定义中，但是*args必须在**kwargs前面。
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>>> def print_everything(*args):
for count, thing in enumerate(args):
... print ('{0}. {1}'.format(count, thing))
...
>>> print_everything('apple', 'banana', 'cabbage')
0. apple
1. banana
2. cabbage
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>>> def table_things(**kwargs):
... for name, value in kwargs.items():
... print ('{0} = {1}'.format(name, value))
...
>>> table_things(apple = 'fruit', cabbage = 'vegetable')
cabbage = vegetable
apple = fruit
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当调用函数时你也可以用、和、*语法。例如：
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>>> def print_three_things(a, b, c):
... print 'a = {0}, b = {1}, c = {2}'.format(a,b,c)
...
>>> mylist = ['aardvark', 'baboon', 'cat']
>>> print_three_things(*mylist)
a = aardvark, b = baboon, c = cat
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两个混在一起用要注意顺序
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def learnarg(*args, **kwargs):
for i in args + tuple(kwargs.values()):
print(i)
for key, value in kwargs.items():
print('{}={}'.format(key, value))
learnarg('Wo', 4, 'KissAndRun', b=7, a=5, c='Hi')
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