id( ) function question

Christian Heimes lists at cheimes.de
Wed Oct 14 13:32:45 CEST 2009


Andre Engels schrieb:
> What is going on is that a few objects that are often used, in
> particular the small (how small is small depends on the
> implementation) integers, are 'preloaded'. When one of these is then
> referred to, a new object is not created, but the pre-defined object
> is used. 10 is apparently a preloaded constant in your implementation,
> 1e10 is not.
> 
> As far as I know, only None is _guaranteed_ to be such a preloaded
> object, so one should not rely on it in implementations.

None, True, False, NotImplemented are guaranteed to be singletons, all
builtin types and exceptions can be considered as singletons, too.

Christian




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