Re: Regular expression : non capturing groups are faster ?

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From	Devin Jeanpierre <jeanpierreda@gmail.com>
Date	Tue, 3 Jan 2012 15:38:36 -0500
Subject	Re: Regular expression : non capturing groups are faster ?
To	Octavian Rasnita <orasnita@gmail.com>
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> I tested 10 million matches on my computer using capturing groups and it took ~ 6 seconds, but only ~ 2 seconds with non-capturing params.

Are you talking about Python or Perl? I can't reproduce this in
Python. Best I can do is a 3:4 ratio between running times. ('(a)*
versus '(?:a)*)

Also, wouldn't say "very fast". Compare those two groups with 'a*'.
I'm not sure what's going on there.

-- Devin

On Tue, Jan 3, 2012 at 3:07 PM, Octavian Rasnita <orasnita@gmail.com> wrote:
> From: "Devin Jeanpierre" <jeanpierreda@gmail.com>
> Subject: Re: Regular expression : non capturing groups are faster ?
>
>
>>> You meant Perl Documentation, didn't you ?
>>
>> I guess that works too. I did mean Python, though -- its intent is to
>> say "you shouldn't worry about this", but in the process it says "this
>> does not exist" (a lie).
>
>
> **
> However, the Perl documentation doesn't lie.
>
> I tested 10 million matches on my computer using capturing groups and it took ~ 6 seconds, but only ~ 2 seconds with non-capturing params.
>
> So yes, it is very fast anyway, but ~ 3 times faster with non-capturing params, so there is a difference.
>
> Octavian
>
> --
> http://mail.python.org/mailman/listinfo/python-list

Thread

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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