Created on 2007-05-18 20:12 by goatchurch, last changed 2010-08-21 23:53 by georg.brandl. This issue is now closed.
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| msg32073 - (view) | Author: Julian Todd (goatchurch) | Date: 2007-05-18 20:12 | |
import re s = "Add.1, 2020 and Add.1, 2021-2023, 2025, 2028 and 2029 and Add.1) R" r = "(?:\s|,|and|Add\S*?|Parts?|\([^\)]*\)|[IV\-\d]+)*$" print "It's going to crash" print re.search(r, s) print "It hasn't crashed" |
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| msg32074 - (view) | Author: Georg Brandl (georg.brandl) *  |
Date: 2007-05-18 20:55 | |
I assume this is one of the pathological cases where the RE algorithm backtracks "to death". That's not really a bug, but a limitation. |
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| msg32075 - (view) | Author: Julian Todd (goatchurch) | Date: 2007-05-18 22:37 | |
I can shorten it further to: s = "Add.1, 2020 Add.1, 20212023, 2025, 2028 and 2029 Add.1) R" r = "(?:\s|,|and|Add\S*?|[\d]+)*$" Sometimes it finishes after a long time when you shorten the s-string from the front. If you take the "R" from the end it goes through straight away. It's even very slow with match. |
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| msg73983 - (view) | Author: Jeffrey C. Jacobs (timehorse) | Date: 2008-09-28 19:12 | |
Tested on 2.6rc2 and slow but successful. Issue 1662851 may be related. |
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| msg81421 - (view) | Author: Matthew Barnett (mrabarnett) | Date: 2009-02-08 21:34 | |
This problem has been addressed in issue #2636. Although the extra checks certainly aren't foolproof, neither of the examples given are slow. |
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| msg114612 - (view) | Author: Georg Brandl (georg.brandl) * |
Date: 2010-08-21 23:53 | |
If at all, this will be fixed by applying #2636. |
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| History | |||
|---|---|---|---|
| Date | User | Action | Args |
| 2010-08-21 23:53:41 | georg.brandl | set | status: open -> closed resolution: duplicate superseder: Adding a new regex module (compatible with re) messages: + msg114612 |
| 2009-02-08 21:34:12 | mrabarnett | set | nosy:
+ mrabarnett messages: + msg81421 |
| 2008-09-28 19:12:53 | timehorse | set | messages: + msg73983 |
| 2008-09-28 19:04:25 | timehorse | set | nosy:
+ timehorse versions: + Python 2.7, - Python 2.4 |
| 2008-04-24 21:12:05 | rsc | set | nosy: + rsc |
| 2007-05-18 20:12:09 | goatchurch | create | |