[Python-ideas] Proposed convenience functions for re module

[Gerald Britton]

Why not:

from itertools import starmap
for x in starmap(re.match, *patterns):
  if x: break

On Tue, Jul 21, 2009 at 8:50 PM, MRAB<python at mrabarnett.plus.com> wrote:
> Steven D'Aprano wrote:
>>
>> Following the thread "Experiment: Adding "re" to string objects.", I would
>> like to propose the addition of two convenience functions to the re module:
>>
>>
>> def multimatch(s, *patterns):
>>    """Do a re.match on s using each pattern in patterns,    returning the
>> first one to succeed, or None if they all fail."""
>>    for pattern in patterns:
>>        m = re.match(pattern, s)
>>        if m: return m
>>
>> def multisearch(s, *patterns):
>>    """Do a re.search on s using each pattern in patterns,    returning the
>> first one to succeed, or None if they all fail."""
>>    for pattern in patterns:
>>        m = re.search(pattern, s)
>>        if m: return m
>>
>>
>> The rationale is to make the following idiom easier:
>>
>>
>> m = re.match(s, pattern1)
>> if not m:
>>    m = re.match(s, pattern2)
>>    if not m:
>>        m = re.match(s, pattern3)
>>        if not m:
>>            m = re.match(s, pattern4)
>> if m:
>>    m.group()
>>
>>
>> which will become:
>>
>> m = re.multimatch(s, pattern1, pattern2, pattern3, pattern4)
>> if m:
>>    m.group()
>>
>>
>> Is there any support or objections to this proposal? Any comments?
>>
> Extend the current re.match and re.search to accept a tuple of patterns:
>
>    m = re.match((pattern1, pattern2, pattern3, pattern4), s)
>    if m:
>        print m.group()
>
> This format is already used by some string methods, eg str.startswith().
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-- 
Gerald Britton