Re: Feature suggestion: sum() ought to use a compensated summation algorithm


On Sat, 2008-05-03 at 21:37 +0000, Ivan Illarionov wrote:
On Sat, 03 May 2008 20:44:19 +0200, Szabolcs Horvát wrote:

Arnaud Delobelle wrote:

sum() works for any sequence of objects with an __add__ method, not
just floats! Your algorithm is specific to floats.

This occurred to me also, but then I tried

sum(['abc', 'efg'], '')

Interesting, I always thought that sum is like shortcut of
reduce(operator.add, ...), but I was mistaken.

reduce() is more forgiving:
reduce(operator.add, ['abc', 'efg'], '' ) # it works
'abcefg'

Hm, it works for lists:
sum(([1], [2]), [])
[1, 2]

However I find the seccond argument hack ugly.
Does the sum way have any performance advantages over the reduce way?

--
Best Regards,
Med Venlig Hilsen,
Thomas

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