Surprise using the 'is' operator

Antoon Pardon apardon at forel.vub.ac.be
Tue Sep 26 15:42:43 CEST 2006


On 2006-09-26, John Roth <JohnRoth1 at jhrothjr.com> wrote:
>
> Antoon Pardon wrote:
>>
>> I find this a bit oddly worded. Now the "may always reuse" phrase
>> suggests this is not an obligation and I can certainly understand
>> that in the case of integers. But when you enumerate examples you
>> include None and Booleans, creating the suggestion these don't
>> have to be implemented as singletons either and that there can be
>> more than one None, True and False object. Now I probably just
>> misunderstand, but I'm wondering, is there somewhere in the language
>> reference that specifies these have to be singletons?
>
> Yes. The topic "The standard Type Hierarchy" in the
> Language reference specifies this exactly.

Thank you very much.

-- 
Antoon Pardon



More information about the Python-list mailing list