mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-12-15 21:44:50 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 12

gh-122055: Clarify documentation for empty matches in RE (GH-133169)

Browse source
This commit is contained in:
Serhiy Storchaka 2025-05-19 16:27:50 +03:00 • committed by GitHub
parent 605022aeb6
commit 44b73d3cd4
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
1 changed files with 9 additions and 7 deletions
Download patch file Download diff file Expand all files Collapse all files

16
Doc/library/re.rst
View file

@ -991,8 +991,8 @@ Functions
That way, separator components are always found at the same relative
indices within the result list.
Empty matches for the pattern split the string only when not adjacent
to a previous empty match.
Adjacent empty matches are not possible, but an empty match can occur
immediately after a non-empty match.
.. code:: pycon
@ -1095,9 +1095,12 @@ Functions
The optional argument *count* is the maximum number of pattern occurrences to be
replaced; *count* must be a non-negative integer. If omitted or zero, all
occurrences will be replaced. Empty matches for the pattern are replaced only
when not adjacent to a previous empty match, so ``sub('x*', '-', 'abxd')`` returns
``'-a-b--d-'``.
occurrences will be replaced.
Adjacent empty matches are not possible, but an empty match can occur
immediately after a non-empty match.
As a result, ``sub('x*', '-', 'abxd')`` returns ``'-a-b--d-'``
instead of ``'-a-b-d-'``.
.. index:: single: \g; in regular expressions
@ -1128,8 +1131,7 @@ Functions
.. versionchanged:: 3.7
Unknown escapes in *repl* consisting of ``'\'`` and an ASCII letter
now are errors.
Empty matches for the pattern are replaced when adjacent to a previous
non-empty match.
An empty match can occur immediately after a non-empty match.
.. versionchanged:: 3.12
Group *id* can only contain ASCII digits.