[New-bugs-announce] [issue13126] find() slower than rfind()

[Antoine Pitrou]

New submission from Antoine Pitrou <pitrou at free.fr>:

With some gcc versions, str.find() is slower than str.rfind():

 - 	11.22	0.0	s="ABC"*33; ((s+"D")*500+s+"E").find(s+"E") (*100)
 - 	4.56	0.0	s="ABC"*33; ((s+"D")*500+"E"+s).find("E"+s) (*100)
 - 	6.71	0.0	s="ABC"*33; (s+"E") in ((s+"D")*300+s+"E") (*100)
 - 	11.22	0.0	s="ABC"*33; ((s+"D")*500+s+"E").index(s+"E") (*100)
 - 	11.52	0.0	s="ABC"*33; ((s+"D")*500+s+"E").partition(s+"E") (*100)
 - 	8.79	0.0	s="ABC"*33; ("E"+s+("D"+s)*500).rfind("E"+s) (*100)
 - 	3.86	0.0	s="ABC"*33; (s+"E"+("D"+s)*500).rfind(s+"E") (*100)
 - 	8.80	0.0	s="ABC"*33; ("E"+s+("D"+s)*500).rindex("E"+s) (*100)
 - 	9.80	0.0	s="ABC"*33; ("E"+s+("D"+s)*500).rpartition("E"+s) (*100)
 - 	9.83	0.0	s="ABC"*33; ("E"+s+("D"+s)*500).rsplit("E"+s, 1) (*100)
 - 	11.56	0.0	s="ABC"*33; ((s+"D")*500+s+"E").split(s+"E", 1) (*100)


Attached patch seems to fix it.

----------
components: Interpreter Core
files: findperf.patch
keywords: patch
messages: 145136
nosy: haypo, pitrou
priority: low
severity: normal
status: open
title: find() slower than rfind()
type: performance
versions: Python 3.3
Added file: http://bugs.python.org/file23339/findperf.patch

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue13126>
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