Python *args **kw

当函数的参数不确定时，可以使用*args 和**kwargs，*args 没有key值，**kwargs有key值。

• *args

def fun_var_args(farg, *args):
    print "arg:", farg  
    for value in args:   # *args可以当作可容纳多个变量组成的list  
        print "another arg:", value

fun_var_args(1,'aa',123,'bb')

#输出
arg: 1
another arg: aa
another arg: 123
another arg: bb

• **kw

def fun_var_kw(farg, **kw):
    print "arg:", farg
    for key in kw: #**kwargs可以当作容纳多个key和value的dictionary  
        print "another keyword arg: %s: %s" % (key, kw[key])

fun_var_kw(1,a='aa',c=123,b='bb')

• 两者同时使用

def fun_var_arg_and_kw(farg, *args, **kw):
    print "arg:", farg
    for value in args:
        print "another arg:", value
    for key in kw:
        print "another keyword arg: %s: %s" % (key, kw[key])

fun_var_arg_and_kw(1,'qq','ww','ee',a='aa',c=123,b='bb')