Vibha Tripathi wrote: > In the Python re.sub(regex, replacement, subject) > method/function, I need the second argument > 'replacement' to be another regular expression ( not a > string) . So when I find a 'certain kind of string' in > the subject, I can replace it with 'another kind of > string' ( not a predefined string ). Note that the > 'replacement' may depend on what exact string is found > as a result of match with the first argument 'regex'. > > Please let me know if the question is not clear.
It's still not very clear, but my guess is you want to supply a replacement function instead of a replacement string, e.g.: py> help(re.sub) Help on function sub in module sre: sub(pattern, repl, string, count=0) Return the string obtained by replacing the leftmost non-overlapping occurrences of the pattern in string by the replacement repl. repl can be either a string or a callable; if a callable, it's passed the match object and must return a replacement string to be used. py> def repl(match): ... print match.group() ... return '46' ... py> re.sub(r'x.*?x', repl, 'yxyyyxxyyxyy') xyyyx xyyx 'y4646yy' STeVe -- http://mail.python.org/mailman/listinfo/python-list