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| From | "Octavian Rasnita" <orasnita@gmail.com> |
| To | <python-list@python.org> |
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| Subject | Re: Regular expression : non capturing groups are faster ? |
| Date | Tue, 3 Jan 2012 13:59:27 +0200 |
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From: "candide" <candide@free.invalid> Subject: Regular expression : non capturing groups are faster ? Excerpt from the Regular Expression HOWTO (http://docs.python.org/howto/regex.html#non-capturing-and-named-groups) : ----------------------------------------------- It should be mentioned that there’s no performance difference in searching between capturing and non-capturing groups; neither form is any faster than the other. ----------------------------------------------- Now from the Perl Regular Expression tutorial (http://perldoc.perl.org/perlretut.html#Non-capturing-groupings) : ----------------------------------------------- Because there is no extraction, non-capturing groupings are faster than capturing groupings. ----------------------------------------------- The second assertion sounds more likely. It seems very odd that Python and Perl implementations are divergent on this point. Any opinion ? -- ** At least in Perl's case, it is true. I tested and using (?:...) is much faster than (). Of course, it takes a few seconds for dozen million matches... Octavian
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Regular expression : non capturing groups are faster ? candide <candide@free.invalid> - 2012-01-03 12:14 +0100
Re: Regular expression : non capturing groups are faster ? Devin Jeanpierre <jeanpierreda@gmail.com> - 2012-01-03 06:56 -0500
Re: Regular expression : non capturing groups are faster ? candide <candide@free.invalid> - 2012-01-03 15:50 +0100
Re: Regular expression : non capturing groups are faster ? Devin Jeanpierre <jeanpierreda@gmail.com> - 2012-01-03 14:31 -0500
Re: Regular expression : non capturing groups are faster ? "Octavian Rasnita" <orasnita@gmail.com> - 2012-01-03 22:07 +0200
Re: Regular expression : non capturing groups are faster ? Devin Jeanpierre <jeanpierreda@gmail.com> - 2012-01-03 15:38 -0500
Re: Regular expression : non capturing groups are faster ? "Octavian Rasnita" <orasnita@gmail.com> - 2012-01-03 13:59 +0200
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