[New-bugs-announce] [issue2607] why is (default)dict so slow on tuples???
report at bugs.python.org
Thu Apr 10 18:21:41 CEST 2008
New submission from Andreas Eisele <eisele at dfki.de>:
I need to count pairs of strings, and I use
a defaultdict in a construct like
count[a,b] += 1
I am able to count 50K items per second on a very fast machine,
which is way too slow for my application.
If I count complete strings like
count[ab] += 1
it can count 500K items/second, which is more reasonable.
I don't see why there is a performance penalty of a factor
of 10 for such a simple construct.
Do I have to switch to Perl or C to get this done???
Thanks a lot for any insight on this.
PS.: The problem seems to exist for ordinary
dicts as well, it is not related to the fact that
I use a defaultdict
PPS: I also tried nested defaultdicts
count[a][b] += 1
and get the same slow speed (and 50% more memory consumption)
title: why is (default)dict so slow on tuples???
versions: Python 2.5
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