question od default args

Gonçalo Rodrigues op73418 at
Wed Jun 26 20:03:08 CEST 2002

On Wed, 26 Jun 2002 17:50:42 GMT, Hans Nowak <wurmy at>

>Gonçalo Rodrigues wrote:
>> Hi,
>> When I want default args I usually do
>> def (arg = None):
>>     ...
>> But what if I want to make None a reasonable argument too? That is, I
>> want to know if the user has in fact passed an argument, and if not to
>> do something special, with None (or whatever object) being a reasonable
>> arg to be passed.
>Hmm, so use a default argument that is not reasonable to pass... some weird 
>string, or a complex number, or even an instance of a (singleton?) class 
>written especially for this... although that may be a bit overkill. Of course, 
>the question is what is "reasonable" here and what not...

In principle everything is reasonable. But (some variation of) "an
instance of a (singleton?) class written especially for this" is worth a

Gonçalo Rodrigues

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