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have a way to search backwards for re #36095
Description
| BPO | 516762 |
|---|---|
| Nosy | @loewis, @amauryfa |
| Superseder |
Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.
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GitHub fields:
assignee = None
closed_at = <Date 2008-09-22.01:00:03.338>
created_at = <Date 2002-02-13.03:22:55.000>
labels = ['type-feature']
title = 'have a way to search backwards for re'
updated_at = <Date 2014-08-25.10:38:33.476>
user = 'https://bugs.python.org/phr'bugs.python.org fields:
activity = <Date 2014-08-25.10:38:33.476>
actor = 'Drekin'
assignee = 'niemeyer'
closed = True
closed_date = <Date 2008-09-22.01:00:03.338>
closer = 'benjamin.peterson'
components = ['None']
creation = <Date 2002-02-13.03:22:55.000>
creator = 'phr'
dependencies = []
files = []
hgrepos = []
issue_num = 516762
keywords = []
message_count = 7.0
messages = ['53476', '53477', '53478', '72784', '72832', '73549', '225871']
nosy_count = 7.0
nosy_names = ['loewis', 'niemeyer', 'phr', 'amaury.forgeotdarc', 'timehorse', 'mrabarnett', 'Drekin']
pr_nums = []
priority = 'normal'
resolution = 'duplicate'
stage = None
status = 'closed'
superseder = '3825'
type = 'enhancement'
url = 'https://bugs.python.org/issue516762'
versions = []
Activity
phr commentedon Feb 13, 2002
There doesn't seem to be any reasonable way to search
a string backwards for a regular expression, starting
from a given character position. I notice that the
underlying C regular expression implemention supports
a direction flag.
I propose adding a direction flag to the search function
on match objects:
would search in str for r, starting at
location 5000 and searching backwards through
location 0 (the beginning of the string).
This is useful in (for example) text editors where
you want to be able to search forwards or backwards,
or if you're parsing an html file and see a </table>
and want to find the matching <table>, etc.
phr
loewis commentedon Mar 27, 2002
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user_id=21627
Moved to feature requests tracker.
phr commentedon Sep 29, 2003
Logged In: YES
user_id=72053
Another way to do this would be add a direction flag to the
regexp itself, like re.R (for reverse) if R isn't already in use:
or something like that.
I continue to want this feature. It's very handy for writing
web scrapers, which I do fairly frequently.
mrabarnett commentedon Sep 8, 2008
Does this request still stand? I'm working on the re module at the moment.
amauryfa commentedon Sep 9, 2008
Why not? I needed such a feature some time ago.
But if possible, it should be a keyword argument:
re.search(..., backwards=True)
similar to list.sort(reverse=True)
mrabarnett commentedon Sep 22, 2008
Implemented as part of bpo-3825.
Drekin commentedon Aug 25, 2014
Hello, I wanted to use this feature and found this issue. It is marked as closed, being a duplicate of another closed issue. However the feature is actually not present. In 2008 it was planned to be added by Matthew Barnett in bpo-3825, but the work of improving re module moved to bigger project under bpo-2636 which resulted in regex package to be evenually included in stdlib. So unless regex is included in stdlib, one should try regex package (e.g. pip install regex).
I've put here this summary just in case there is someone like me who looked for the feature and found this issue.