*args and **kwargs

[Smith]

On 02/09/2016 16:52, alister wrote:
> On Fri, 02 Sep 2016 23:44:50 +1000, Ben Finney wrote:
>
>> Smith <smith at smith.com> writes:
>>
>>> I'm trying to understand the concept of * args and ** kwarg with
>>> python3
>>
>> Welcome. Your questions are fine in this forum; but you may also want to
>> participate in our collaborative learning forum for Python beginners,
>> <URL:https://mail.python.org/mailman/listinfo/tutor>.
>>
>>> But I can not understand why I returns the error message "SyntaxError:
>>> positional argument follows the keyword argument" when I insert values.
>>
>> It's fairly simple (though it may not be obvious!):
>>
>>> In [23]: start(data="Fish",2,3,tox="tux")
>>>   File "<ipython-input-23-eb9c3abb9941>", line 1
>>>     start(data="Fish",2,3,tox="tux")
>>>                      ^
>>> SyntaxError: positional argument follows keyword argument
>>
>> Exactly.
>>
>> Note that this has nothing to do with how the function is defined; in
>> the definition of the function, parameters are neither positional nor
>> keyword. You name each of them, and you define an order for them; and
>> neither of those makes any of them “positional” or “keyword”.
>>
>> Rather, “positional argument and “keyword argument” are characteristics
>> of the arguments you *supply* in a particular call to the function.
>>
>> You have specified four arguments, in this order:
>>
>>   * A keyword argument, ‘data="Fish"’.
>>   * A positional argument, ‘2’.
>>   * A positional argument, ‘3’.
>>   * A keyword argument, ‘tox="tux"’.
>>
>> After specifying a keyword argument, you may not then specify any
>> positional arguments. Hence the SyntaxError.
>
>
> & the solution is to change the order of the definition
>
> def start( must_have,*args,**kwargs,data=none):
>
>
>
thanks a lot