Match groups in Python

Question

Is there a way in Python to access match groups without explicitly creating a match object (or another way to beautify the example below)?

Here is an example to clarify my motivation for the question:

Following Perl code

if    ($statement =~ /I love (\w+)/) {   print "He loves $1\n"; } elsif ($statement =~ /Ich liebe (\w+)/) {   print "Er liebt $1\n"; } elsif ($statement =~ /Je t\'aime (\w+)/) {   print "Il aime $1\n"; } 

translated into Python

m = re.search("I love (\w+)", statement) if m:   print "He loves",m.group(1) else:   m = re.search("Ich liebe (\w+)", statement)   if m:     print "Er liebt",m.group(1)   else:     m = re.search("Je t'aime (\w+)", statement)     if m:       print "Il aime",m.group(1) 

looks very awkward (if-else-cascade, match object creation).

Answer 1

You could create a little class that returns the boolean result of calling match, and retains the matched groups for subsequent retrieval:

import re  class REMatcher(object):     def __init__(self, matchstring):         self.matchstring = matchstring      def match(self,regexp):         self.rematch = re.match(regexp, self.matchstring)         return bool(self.rematch)      def group(self,i):         return self.rematch.group(i)   for statement in ("I love Mary",                    "Ich liebe Margot",                    "Je t'aime Marie",                    "Te amo Maria"):      m = REMatcher(statement)      if m.match(r"I love (\w+)"):          print "He loves",m.group(1)       elif m.match(r"Ich liebe (\w+)"):         print "Er liebt",m.group(1)       elif m.match(r"Je t'aime (\w+)"):         print "Il aime",m.group(1)       else:          print "???" 

Update for Python 3 print as a function, and Python 3.8 assignment expressions - no need for a REMatcher class now:

import re  for statement in ("I love Mary",                   "Ich liebe Margot",                   "Je t'aime Marie",                   "Te amo Maria"):      if m := re.match(r"I love (\w+)", statement):         print("He loves", m.group(1))      elif m := re.match(r"Ich liebe (\w+)", statement):         print("Er liebt", m.group(1))      elif m := re.match(r"Je t'aime (\w+)", statement):         print("Il aime", m.group(1))      else:         print()