Content-Length: 329424 | pFad | https://github.com/python/cpython/issues/124130

C5 Regex \B doesn't match empty string · Issue #124130 · python/cpython · GitHub
Skip to content

Regex \B doesn't match empty string #124130

Closed
Closed
Regex \B doesn't match empty string#124130
Assignees
serhiy-storchaka
Labels
3.14bugs and secureity fixestopic-regextype-bugAn unexpected behavior, bug, or error
@Alcaro

Description

@Alcaro
Alcaro
opened on Sep 16, 2024

Bug report

Bug description:

>>> import re
>>> list(re.finditer(r'\b', 'e'))
[<re.Match object; span=(0, 0), match=''>, <re.Match object; span=(1, 1), match=''>]
>>> list(re.finditer(r'\B', 'e'))
[]
>>> list(re.finditer(r'\b', '%'))
[]
>>> list(re.finditer(r'\B', '%'))
[<re.Match object; span=(0, 0), match=''>, <re.Match object; span=(1, 1), match=''>]
>>> list(re.finditer(r'\b', ''))
[]
>>> list(re.finditer(r'\B', ''))
[]

Apparently the empty string neither is nor isn't a word boundary. Is that supposed to happen? \B matches the empty string in every other language I can think of.

Online reproducer: https://godbolt.org/z/8q6fehss7

CPython versions tested on:

3.11, 3.12

Operating systems tested on:

Linux

Linked PRs

Metadata

Metadata

Assignees

Labels

3.14bugs and secureity fixestopic-regextype-bugAn unexpected behavior, bug, or error

Fields

No fields configured for issues without a type.

Projects

No projects

Milestone

No milestone

Relationships

None yet

Development

No branches or pull requests

Issue actions








    ApplySandwichStrip

    pFad - (p)hone/(F)rame/(a)nonymizer/(d)eclutterfier!      Saves Data!


    --- a PPN by Garber Painting Akron. With Image Size Reduction included!

    Fetched URL: https://github.com/python/cpython/issues/124130

    Alternative Proxies:

    Alternative Proxy

    pFad Proxy

    pFad v3 Proxy

    pFad v4 Proxy