[Python-Dev] Re: accumulator display syntax
Guido van Rossum
guido at python.org
Mon Oct 20 14:15:22 EDT 2003
> Most of us seem to agree that having list comprehensions
> available as a replacement for map() and filter() is a good
> thing. But what about reduce()? Are there equally strong
> reasons for wanting an alternative to that, too? If not,
> why not?
If anything, the desire there is *more* pressing. Except for
operator.add, expressions involving reduce() are notoriously hard to
understand (except to experienced APL or Scheme hackers :-).
Things like sum, max, average etc. are expressed very elegantly with
iterator comprehensions.
I think the question is more one of frequency of use. List comps have
nothing over e.g.
result = []
for x in S:
result.append(x**2)
except compactness of exprssion. How frequent is
result = 0.0
for x in S:
result += x**2
???
(I've already said my -1 about your 'sum of ...' proposal.)
--Guido van Rossum (home page: http://www.python.org/~guido/)
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