--- On Wed, 11/3/10, MRAB wrote:
> [snip]
> The outer group is repeated, so it can match again, but the
> inner group
> can't match again because it captured all it could the
> previous time.
>
> Therefore the outer group matches and captures an empty
> string and the
> inner group remembers its
On 03/11/2010 06:32, Yingjie Lan wrote:
--- On Wed, 11/3/10, John Bond wrote:
I just explained that (I think!)! The outer capturing group
uses
repetition, so it returns the last thing that was matched
by the inner
group, which was an empty string.
According to yourself, the last match of the
On 03/11/2010 04:10, John Bond wrote:
On 3/11/2010 4:02 AM, MRAB wrote:
On 03/11/2010 03:42, Yingjie Lan wrote:
Matches an empty string, returns ''
The result is therefore ['Mar', '', '', 'lam', '', '']
Thanks, now I see it through with clarity.
Both you and JB are right about this case.
How
hen the last
match for the inner group must
also be empty.
Regards,
Yingjie
--- On Wed, 11/3/10, John Bond wrote:
> From: John Bond
> Subject: Re: Must be a bug in the re module [was: Why this result with the re
> module]
> To: python-list@python.org
> Date: Wednesday, November
--- On Wed, 11/3/10, John Bond wrote:
>3) then said there must be >=0 occurrences of what's inside it,
>which of course there is, so that has no effect.
>
>((.a.)*)*
Hi,
I think there should be a difference: unlike before,
now what's inside the outer group can match an empty
s
On 3/11/2010 4:23 AM, Yingjie Lan wrote:
--- On Wed, 11/3/10, MRAB wrote:
From: MRAB
Subject: Re: Must be a bug in the re module [was: Why this result with the re
module]
To: python-list@python.org
Date: Wednesday, November 3, 2010, 8:02 AM
On 03/11/2010 03:42, Yingjie Lan
wrote:
Therefore
OK, I've got that, and I have no problem with the capturing part.
My real problem is with the number of total matches.
*I think it should be 4 matches in total but findall
gives 6 matches*, for the new regex '((.a.)*)*'.
I'd love to know what you think about this.
Many thanks!
Yingjie
We'v
--- On Wed, 11/3/10, MRAB wrote:
> From: MRAB
> Subject: Re: Must be a bug in the re module [was: Why this result with the re
> module]
> To: python-list@python.org
> Date: Wednesday, November 3, 2010, 8:02 AM
> On 03/11/2010 03:42, Yingjie Lan
> wrote:
> Therefore th
--- On Wed, 11/3/10, John Bond wrote:
> Just to clarify - findall is returning:
>
> [ (only match in outer group, 1st match in inner group)
> , (only match in outer group, 2nd match in inner group)
> , (only match in outer group, 3rd match in inner group)
> , (only match in outer group, 4th mat
On 3/11/2010 4:02 AM, MRAB wrote:
On 03/11/2010 03:42, Yingjie Lan wrote:
Matches an empty string, returns ''
The result is therefore ['Mar', '', '', 'lam', '', '']
Thanks, now I see it through with clarity.
Both you and JB are right about this case.
However, what if the regex is ((.a.)*)* ?
On 3/11/2010 3:55 AM, John Bond wrote:
Could you please reconsider how would you
work with this new one and see if my steps
are correct? If you agree with my 7-step
execution for the new regex, then:
We finally found a real bug for re.findall:
re.findall('((.a.)*)*', 'Mary has a lamb')
[(''
On 03/11/2010 03:42, Yingjie Lan wrote:
Matches an empty string, returns ''
The result is therefore ['Mar', '', '', 'lam', '', '']
Thanks, now I see it through with clarity.
Both you and JB are right about this case.
However, what if the regex is ((.a.)*)* ?
Actually, in hindsight, my explan
Could you please reconsider how would you
work with this new one and see if my steps
are correct? If you agree with my 7-step
execution for the new regex, then:
We finally found a real bug for re.findall:
re.findall('((.a.)*)*', 'Mary has a lamb')
[('', 'Mar'), ('', ''), ('', ''), ('', 'lam'
> Matches an empty string, returns ''
>
> The result is therefore ['Mar', '', '', 'lam', '', '']
Thanks, now I see it through with clarity.
Both you and JB are right about this case.
However, what if the regex is ((.a.)*)* ?
--
http://mail.python.org/mailman/listinfo/python-list
> Your regex says "Zero or more consecutive occurrences of
> something, always returning the most possible". That's
> what it does, at every position - only matching emptyness
> where it couldn't match anything (findall then skips a
> character to avoid overlapping/infinite empty
> matches), and
On 03/11/2010 01:41, Yingjie Lan wrote:
From: John Bond
Subject: Re: Why this result with the re module
To: "Yingjie Lan"
Cc: python-list@python.org
Date: Tuesday, November 2, 2010, 8:09 PM
On 2/11/2010 12:19 PM, Yingjie Lan
wrote:
From: John Bond
Subject: Re: Why this result with the re module
Disagree in this case, where the whole regex
matches an empty string. Greadiness will match
as much as possible. So it will also match
the empty strings between consecutive
characters as much as possible, once
we have properly defined all the unique
empty strings. Because of greadiness,
fewer ma
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