[Python-Dev] PEP 289 - Generator Expressions - Let's Move Forward

Jeremy Hylton jeremy at alum.mit.edu
Fri Apr 23 16:10:39 EDT 2004


On Fri, 2004-04-23 at 15:59, Phillip J. Eby wrote:
> At 03:41 PM 4/23/04 -0400, Jeremy Hylton wrote:
> 
> >That leads me to wonder what exactly the rationale for generator
> >expressions is.  The PEP says that "time, clarity, and memory are
> >conserved by using an generator expression" but I can only see how
> >memory is conserved.  That is, I don't find them any easier to read than
> >list comprehensions and I don't understand the performance implications
> >very well.  It's not obvious to me that their faster.
> 
> Alex Martelli previously posted some tests that showed them to be quite a 
> bit faster for large lists.

Anyone know where to find these numbers.  I've done some searching, but
I can't find them.  It would be good to include something concrete in
the PEP.

Jeremy





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