Python定义函数中的可变参数**kw及*args

def ss(a,b,*args,**kw):
print('fist position:',a)
print('second position:',b)
print('third position:',args)
print('fourth position:',kw)

ss(12,33,city='shanghai')

fist position: 12
second position: 33
third position: ()
fourth position: {'city': 'shanghai'}

ss(12,33,'shanghai')

fist position: 12
second position: 33
third position: ('shanghai',)
fourth position: {}