Re: Why is regex so slow?

From	roy@panix.com (Roy Smith)
Newsgroups	comp.lang.python
Subject	Re: Why is regex so slow?
Date	2013-06-18 15:21 -0400
Organization	PANIX -- Public Access Networks Corp.
Message-ID	<kpqc0a$8am$1@panix2.panix.com> (permalink)
References	<kpq2r9$gg6$1@panix2.panix.com> <CANc-5UyouN5EQw_GDecaAR+inyAB26g=e2pZ=zBuspXdmxJh+Q@mail.gmail.com> <B2AEBA54-6098-47D6-B7E0-77F0B7D8D722@panix.com> <mailman.3549.1371576854.3114.python-list@python.org>

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In article <mailman.3549.1371576854.3114.python-list@python.org>,
Mark Lawrence  <breamoreboy@yahoo.co.uk> wrote:

> Out of curiousity have the tried the new regex module from pypi rather 
> than the stdlib version?  A heck of a lot of work has gone into it see 
> http://bugs.python.org/issue2636

I just installed that and gave it a shot.  It's *slower* (and, much
higher variation from run to run).  I'm too exhausted fighting with
OpenOffice to get this into some sane spreadsheet format, so here's
the raw timings:

Built-in re module:
0:01.32
0:01.33
0:01.32
0:01.33
0:01.35
0:01.32
0:01.35
0:01.36
0:01.33
0:01.32

regex with flags=V0:
0:01.66
0:01.53
0:01.51
0:01.47
0:01.81
0:01.58
0:01.78
0:01.57
0:01.64
0:01.60

regex with flags=V1:
0:01.53
0:01.57
0:01.65
0:01.61
0:01.83
0:01.82
0:01.59
0:01.60
0:01.55
0:01.82

Thread

Why is regex so slow? roy@panix.com (Roy Smith) - 2013-06-18 12:45 -0400
  Re: Why is regex so slow? Skip Montanaro <skip@pobox.com> - 2013-06-18 12:01 -0500
  Re: Why is regex so slow? Roy Smith <roy@panix.com> - 2013-06-18 13:08 -0400
  Re: Why is regex so slow? Chris Angelico <rosuav@gmail.com> - 2013-06-19 03:20 +1000
    Re: Why is regex so slow? Johannes Bauer <dfnsonfsduifb@gmx.de> - 2013-06-18 20:10 +0200
      Re: Why is regex so slow? Roy Smith <roy@panix.com> - 2013-06-18 12:40 -0700
      Re: Why is regex so slow? André Malo <ndparker@gmail.com> - 2013-06-18 21:59 +0200
        Re: Why is regex so slow? André Malo <ndparker@gmail.com> - 2013-06-18 22:13 +0200
  Re: Why is regex so slow? MRAB <python@mrabarnett.plus.com> - 2013-06-18 18:31 +0100
  Re: Why is regex so slow? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-06-18 18:34 +0100
    Re: Why is regex so slow? roy@panix.com (Roy Smith) - 2013-06-18 15:21 -0400
      Re: Why is regex so slow? MRAB <python@mrabarnett.plus.com> - 2013-06-18 20:49 +0100
  Re: Why is regex so slow? Rick Johnson <rantingrickjohnson@gmail.com> - 2013-06-18 12:21 -0700
  Re: Why is regex so slow? Antoine Pitrou <solipsis@pitrou.net> - 2013-06-18 20:05 +0000
    Re: Why is regex so slow? Roy Smith <roy@panix.com> - 2013-06-18 13:23 -0700
      Re: Why is regex so slow? Duncan Booth <duncan.booth@invalid.invalid> - 2013-06-19 13:21 +0000
        Re: Why is regex so slow? Roy Smith <roy@panix.com> - 2013-06-19 12:55 -0700
    Re: Why is regex so slow? Grant Edwards <invalid@invalid.invalid> - 2013-06-18 20:30 +0000
      Re: Why is regex so slow? Terry Reedy <tjreedy@udel.edu> - 2013-06-18 17:29 -0400
      Re: Why is regex so slow? Johannes Bauer <dfnsonfsduifb@gmx.de> - 2013-06-19 10:29 +0200
  Re: Why is regex so slow? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-19 01:51 +0000
    Re: Why is regex so slow? Dave Angel <davea@davea.name> - 2013-06-18 22:11 -0400
      Re: Why is regex so slow? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-19 03:16 +0000

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