attribute access and comparisons of two different objects

Michele Simionato michele.simionato at
Wed Jun 16 06:08:22 CEST 2004

"Larry Bates" <lbates at> wrote in message news:<V4KdnTIF-4yRZFPdRVn-ug at>...
> 1) In Python 2.3 there is a new __slots__ methodology that
> does what you want with class attributes.  One must wonder
> how everyone got by without it for so many years.  I'm not
> sure I understand the "overhead" issue.  Some code must be
> executed to determine if an attribute exists or not, why
> shouldn't it be up to the programmer to write it by
> overriding __setattr__ method?

__slots__ should never be used to restrict attribute access;
they are just a memory saving optimization; you are better off
not using it if you can. See this recipe:

Yes, overriding __setattr__ has a performance overhaud, so
just do not freeze your attributes! That's the Pythonic solution.

   Michele Simionato

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