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devel / comp.lang.python / RE: Regular Expression bug?

RE: Regular Expression bug?

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Subject: RE: Regular Expression bug?
Date: Thu, 2 Mar 2023 20:35:12 -0500
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by: - Fri, 3 Mar 2023 01:35 UTC

It is a well-known fact, Jose, that GIGO.

The letters "n" and "m" are not interchangeable. Your pattern fails because you have "pn" in one place and "pm" in the other.

>>> s = "pn=jose pn=2017"
....
>>> s0 = r0.match(s)
>>> s0
<re.Match object; span=(0, 15), match='pn=jose pn=2017'>

-----Original Message-----
From: Python-list <python-list-bounces+avi.e.gross=gmail.com@python.org> On Behalf Of jose isaias cabrera
Sent: Thursday, March 2, 2023 8:07 PM
To: Mats Wichmann <mats@wichmann.us>
Cc: python-list@python.org
Subject: Re: Regular Expression bug?

On Thu, Mar 2, 2023 at 2:38 PM Mats Wichmann <mats@wichmann.us> wrote:
>
> On 3/2/23 12:28, Chris Angelico wrote:
> > On Fri, 3 Mar 2023 at 06:24, jose isaias cabrera <jicman@gmail.com>
wrote:
> >>
> >> Greetings.
> >>
> >> For the RegExp Gurus, consider the following python3 code:
> >> <code>
> >> import re
> >> s = "pn=align upgrade sd=2023-02-"
> >> ro = re.compile(r"pn=(.+) ")
> >> r0=ro.match(s)
> >>>>> print(r0.group(1))
> >> align upgrade
> >> </code>
> >>
> >> This is wrong. It should be 'align' because the group only goes up-to
> >> the space. Thoughts? Thanks.
> >>
> >
> > Not a bug. Find the longest possible match that fits this; as long as
> > you can find a space immediately after it, everything in between goes
> > into the .+ part.
> >
> > If you want to exclude spaces, either use [^ ]+ or .+?.
>
> https://docs.python.org/3/howto/regex.html#greedy-versus-non-greedy

This re is a bit different than the one I am used. So, I am trying to match
everything after 'pn=':

import re
s = "pm=jose pn=2017"
m0 = r"pn=(.+)"
r0 = re.compile(m0)
s0 = r0.match(s)
>>> print(s0)
None

Any help is appreciated.
--
https://mail.python.org/mailman/listinfo/python-list

Subject	Author
RE: Regular Expression bug?	<avi.e.gross