【Python】Python中*args 和**kwargs的用法

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

 def fun_var_args(farg, *args):
     print "arg:", farg
     for value in args:
         print "another arg:", value  

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

result:

 arg:
 another arg: two
 another arg:   

**kwargs:

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

result:

 arg:
 another keyword arg: myarg2: two
 another keyword arg: myarg3:   

也可以用下面的形式：

 def fun_var_args_call(arg1, arg2, arg3):
     print "arg1:", arg1
     print "arg2:", arg2
     print "arg3:", arg3  

 args = ["two", ] #list  

 fun_var_args_call(, *args)  

result：

 arg1:
 arg2: two
 arg3:   

 def fun_var_args_call(arg1, arg2, arg3):
     print "arg1:", arg1
     print "arg2:", arg2
     print "arg3:", arg3  

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

 fun_var_args_call(, **kwargs)  

result：

 arg1:
 arg2:"two"
 arg3: