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#25517: fix regex in the regex howto. Patch by Elena Oat.

This commit is contained in:
Ezio Melotti 2016-01-12 00:09:13 +02:00
parent 7c018aa377
commit 84c63e8df4
1 changed files with 4 additions and 3 deletions
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Doc/howto/regex.rst
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@ -1004,17 +1004,18 @@ confusing.
A negative lookahead cuts through all this confusion:
``.*[.](?!bat$).*$`` The negative lookahead means: if the expression ``bat``
``.*[.](?!bat$)[^.]*$`` The negative lookahead means: if the expression ``bat``
doesn't match at this point, try the rest of the pattern; if ``bat$`` does
match, the whole pattern will fail. The trailing ``$`` is required to ensure
that something like ``sample.batch``, where the extension only starts with
``bat``, will be allowed.
``bat``, will be allowed. The ``[^.]*`` makes sure that the pattern works
when there are multiple dots in the filename.
Excluding another filename extension is now easy; simply add it as an
alternative inside the assertion. The following pattern excludes filenames that
end in either ``bat`` or ``exe``:
``.*[.](?!bat$|exe$).*$``
``.*[.](?!bat$|exe$)[^.]*$``
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