From 84c63e8df4f48a34ad20829125c12db71314f9ef Mon Sep 17 00:00:00 2001 From: Ezio Melotti Date: Tue, 12 Jan 2016 00:09:13 +0200 Subject: [PATCH] #25517: fix regex in the regex howto. Patch by Elena Oat. --- Doc/howto/regex.rst | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/Doc/howto/regex.rst b/Doc/howto/regex.rst index ad2c6ab7d54..70721a9f27f 100644 --- a/Doc/howto/regex.rst +++ b/Doc/howto/regex.rst @@ -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$)[^.]*$`` Modifying Strings