Performance penalty for using properties?

[Aahz]

In article <slrnc55f2n.1qp.kmmcdonald at g4.gateway.2wire.net>,
Kenneth McDonald  <kmmcdonald at wisc.edu> wrote:
>
>Now that I'm back to Python and all the new (to me) cool features,
>I find I'm using properties a lot, i.e. I'm defining:
>
>	foo = property(fset=..., fget=...)
>
>for a number of properties, in many of my classes. I'm not using
>them for anything performance critical yet, but could see myself
>doing so in the future. Can anyone comment on the performance
>costs associated with properties vs. simple attribute lookup?

That's sort-of not the point.  Yes, plain attribute lookups are going to
be faster because they don't involve a function call.  OTOH, new-style
classes already pay a penalty for properties because any simple
attribute lookup on an instance requires checking the whole MRO to make
sure there isn't a property.  Finally, the proper comparison is against
getter/setter methods, which properties encapsulate nicely.
-- 
Aahz (aahz at pythoncraft.com)           <*>         http://www.pythoncraft.com/

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