python中 *args 与 **kwargs

代码段：

# coding:utf-8# args和kwargs都是可变参数，可以直接向里面传参数，并且参数不固定。# 当函数的参数不固定时，可以使用*args 和**kwargs。# 其中*args 没有key值，**kwargs有key值。# **#def args_test(*args):    print "args:", args    for value in args:        # print "value的类型:", type(value)        if type(value) is str:            print "value: %s" % value        elif type(value) is int:            print "value: %d" % value        else:            print "hehe"    print "第二个：", args[1]def kwargs_test(**kwargs):    print "kwargs:", kwargs    for key in kwargs:        print "第%s个： %d" % (key, kwargs[key])    print "第二个：", kwargs['b']if __name__ == "__main__":    args_test(1, 2, 3, 4, 5)    print "--------------------------------------1"    list = [1, 2, 3, 4]    args_test(*list)    print "--------------------------------------2"    tuple = (1, 2, 3, 4)    args_test(*tuple)    print "--------------------------------------3"    # 当向args里面传入dict的时候，会将dict里面的key组合成tuple，value全部被抛弃    dict = {'a': 7, 'b': 8, 'c': 9, 'd': 10}    args_test(*dict)    print "--------------------------------------4"    kwargs_test(a=1, b=2, c=3, d=4, e=5)    print "--------------------------------------5"    dict = {'a': 1, 'b': 2, 'c': 3, 'd': 4}    # 如果想直接传一个字典进来的话，变量前面要加**    kwargs_test(**dict)    print "--------------------------------------6"    # TypeError: kwargs_test() argument after ** must be a mapping, not tuple    tuple = (1, 2, 3, 4, 5)    kwargs_test(**tuple)    print "--------------------------------------7"     # TypeError: kwargs_test() argument after ** must be a mapping, not list    list = [1, 2, 3, 4, 5]    kwargs_test(**list)    print "--------------------------------------8"

运行结果