From a7abb8c8e6970f01d12c34d956b2cc9d31a41235 Mon Sep 17 00:00:00 2001 From: "Miss Islington (bot)" <31488909+miss-islington@users.noreply.github.com> Date: Thu, 19 Jun 2025 17:07:12 +0200 Subject: [PATCH] [3.14] Docs: Add missing lines between regex and text (GH-134505) (GH-135718) Docs: Add missing lines between regex and text (GH-134505) (cherry picked from commit 754190287ece5a2e66684161aadafb18f5f44868) Co-authored-by: Rafael Fontenelle --- Doc/howto/regex.rst | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/Doc/howto/regex.rst b/Doc/howto/regex.rst index e543f6d5657d..7486a378dbb0 100644 --- a/Doc/howto/regex.rst +++ b/Doc/howto/regex.rst @@ -1016,7 +1016,9 @@ extension. This regular expression matches ``foo.bar`` and Now, consider complicating the problem a bit; what if you want to match filenames where the extension is not ``bat``? Some incorrect attempts: -``.*[.][^b].*$`` The first attempt above tries to exclude ``bat`` by requiring +``.*[.][^b].*$`` + +The first attempt above tries to exclude ``bat`` by requiring that the first character of the extension is not a ``b``. This is wrong, because the pattern also doesn't match ``foo.bar``. @@ -1043,7 +1045,9 @@ 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 -- 2.47.3