Python中*args 和**kwargs的用法

http://blog.csdn.net/chenjinyu_tang/article/details/8136841

好久没有学习python了，应为工作的需要，再次拾起python，唤起记忆。

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。

还是直接来代码吧，废话少说

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def fun_var_args(farg, *args):

print "arg:", farg

for value in args:

print "another arg:", value

fun_var_args(1, "two", 3) # *args可以当作可容纳多个变量组成的list

result:

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arg: 1

another arg: two

another arg: 3

**kwargs:

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def fun_var_kwargs(farg, **kwargs):

print "arg:", farg

for key in kwargs:

print "another keyword arg: %s: %s" % (key, kwargs[key])

fun_var_kwargs(farg=1, myarg2="two", myarg3=3) # myarg2和myarg3被视为key， 感觉**kwargs可以当作容纳多个key和value的dictionary

result:

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arg: 1

another keyword arg: myarg2: two

another keyword arg: myarg3: 3

也可以用下面的形式：

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def fun_var_args_call(arg1, arg2, arg3):

print "arg1:", arg1

print "arg2:", arg2

print "arg3:", arg3

args = ["two", 3] #list

fun_var_args_call(1, *args)

result：

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arg1: 1

arg2: two

arg3: 3

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def fun_var_args_call(arg1, arg2, arg3):

print "arg1:", arg1

print "arg2:", arg2

print "arg3:", arg3

kwargs = {"arg3": 3, "arg2": "two"} # dictionary

fun_var_args_call(1, **kwargs)

result：

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arg1: 1

arg2:"two"

arg3:3