[Python-ideas] Proposed convenience functions for re module

July 22, 2009

      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?

-- 
Steven D'Aprano