issue2636-22 : Code : Python (original) (raw)

lp:~pythonregexp2.7/python/issue2636-22

Created byTimeHorse on 2008-09-24 and last modifiedon 2008-09-24

The current implementation of the Python Regular Expression Engine does not allow an expression to be found or split if the length of the Regular Expression match is of zero-length. Rather than splitting the given string as expected, it simply returns the original string in a single-element array, rather than an array containing each character as an element of the output list, as well as an empty string to represent the "first" and "last" characters of a string. For example:

>>> re.split(r'\b', 'a b')
['a b']

When one would expect this to return the list [ '', 'a', ' ', 'b', '' ]. Because some existing python code may expect the single-element unsplit list as a result of a Zero-Width expression, it is recommended that, at least initially, we provide a flag, re.ZEROWIDTH and re.Z as well as an In-Line flag (?z) to enable this behaviour. It may also be possible to add a 'from __future__ import ZeroWidthRegularExpressions" to enable this behaviour by default if this functionality is considered best the best long-term solution. This item is based on the work from Issues 3262, 988761 and 852532.

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39039. ByJeffrey C. "The TimeHorse" Jacobs on 2008-09-21

39038. ByJeffrey C. "The TimeHorse" Jacobs on 2008-06-18

39037. ByJeffrey C. "The TimeHorse" Jacobs on 2008-06-11

39036. ByJeffrey C. "The TimeHorse" Jacobs on 2008-06-09

39035. ByJeffrey C. "The TimeHorse" Jacobs on 2008-06-03

39034. ByJeffrey C. "The TimeHorse" Jacobs on 2008-05-30

39033. ByJeffrey C. "The TimeHorse" Jacobs on 2008-05-29

39032. ByJeffrey C. "The TimeHorse" Jacobs on 2008-05-29

39031. ByJeffrey C. "The TimeHorse" Jacobs on 2008-05-24

39030. ByJeffrey C. "The TimeHorse" Jacobs on 2008-05-22

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