Permanent objects?

[Paul Rubin]

a-steinhoff at web.de (Armin Steinhoff) writes:
> > > >>> x = 99
> > > >>> y = 99
> > > >>> x is y
> >  1
> > > >>> x = 100
> > > >>> y = 100
> > > >>> x is y
> > > 0
> 
> Could someone explain in _detail_ why this happens?

Python heap-allocates numeric objects including integers.  Integers
less than 100 are cached in a table, sort of like interned strings,
since they're used frequently.  Integers >= 100 get newly allocated
since they're more likely to be unique.