← index #8273PR #14179
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QUERY · ISSUE

re module defines re.match both as a function and class

openby Josverlopened 2022-02-07updated 2025-10-03
docs

There appears to be a conflict in both the documentation and the implementation of the re/ure module.

The documentation for the re module specifies that re.match is a function

.. function:: match(regex_str, string)
   Compile *regex_str* and match against *string*. Match always happens
   from starting position in a string.

However it also appears to document that re.match is a class, as there are methods documented.

I would expect that the class would be named Match rather then match

Match objects
-------------
Match objects as returned by `match()` and `search()` methods, and passed
to the replacement function in `sub()`.
.. method:: match.group(index)
   Return matching (sub)string. *index* is 0 for entire match,
   1 and above for each capturing group. Only numeric groups are supported.
.. method:: match.groups()

When checking the implementation ( v1.18) with the below code it appears that there is indeed a class named match returned from the function match.

import re
Substring ='.*Python'
String1 = "MicroPython"
m =re.match(Substring, String1)
print(type(m))
# MicroPython: <class 'match'>
# CPython: <class 're.Match'>

The reason that I noticed this is that I am creating and validating .pyi stubs that are autogenerated from the documentation, and in as part of test and validation noticed this conflict.

Its not to difficult to create another PR to update the documentation, however that would not match the current implementation.
However my main question is: should the implementation be updated to name the class 'Match' ?

CANDIDATE · PULL REQUEST

re: Add support for start- and endpos.

mergedby greezybaconopened 2024-03-26updated 2025-08-11
extmod

This adds support to match the CPython re module which supports searching and matching a substring using a start- and end-pos specified in the corresponding Pattern method.

Pattern objects have two additional parameters for the ::search and ::match methods to define the starting and ending position of the subject within the string to be searched.

This allows for searching a sub-string without creating a slice of the string, which is advantageous for performance and also makes inroads for something like the finditer method.

However, one caveat of using the start-pos rather than a slice is that the start anchor (^) remains anchored to the beginning of the text.

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