Author gerardjp
Recipients BMintern, effbot, gerardjp, mchaput, nneonneo
Date 2008-07-11.08:17:19
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Message-id <1215764240.83.0.656641875209.issue1519638@psf.upfronthosting.co.za>
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Hi All,

I found a workaround for the re.sub method so it does not raise an
exception but returns and empty string when backref-ing an empty group.

This is the nutshell:

When doing a search and replace with sub, replace the group represented
as optional for a group represented as an alternation with one empty
subexpression. So instead of this “(.+?)?” use this “(|.+?)” (without
the double quotes).

If there’s nothing matched by this group the empty subexpression
matches. Then an empty string is returned instead of a None and the sub
method is executed normally instead of raising the “unmatched group” error.

A complete description is in my post:
http://www.gp-net.nl/2008/07/11/solved-python-regex-raising-exception-unmatched-group/


Regards,

Gerard.
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Date User Action Args
2008-07-11 08:17:21gerardjpsetspambayes_score: 0.0743727 -> 0.0743727
recipients: + gerardjp, effbot, mchaput, nneonneo, BMintern
2008-07-11 08:17:20gerardjpsetspambayes_score: 0.0743727 -> 0.0743727
messageid: <1215764240.83.0.656641875209.issue1519638@psf.upfronthosting.co.za>
2008-07-11 08:17:20gerardjplinkissue1519638 messages
2008-07-11 08:17:19gerardjpcreate