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[Python-Dev] Re: accumulator display syntax

Guido van Rossum guido at python.org
Sat Oct 25 16:20:45 EDT 2003 
> sum looks cooler, but it can be an order of magnitude slower
> than the humble loop of result.extend calls.  We could fix this
> specific performance trap by specialcasing in sum those cases
> where the result has a += method -- hmmm... would a patch for
> this performance bug be accepted for 2.3.* ...?  (I understand and
> approve that we're keen on avoiding adding functionality in any
> 2.3.*, but fixed-functionality performance enhancements should
> be just as ok as fixes to functionality bugs, right?)

No way.  There's nothing that guarantees that a+=b has the same
semantics as a+b, and in fact for lists it doesn't.

I wouldn't even want this for 2.4.

--Guido van Rossum (home page: http://www.python.org/~guido/)
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