Schüle Daniel wrote: (snipped)
> I am trying to construct a case where a greedy and > non greedy operation produce different result. > I dont see the difference between 'a??b' and 'a?b' > As far I understand is that ? will first try to match a > (it's greedy) and only if it fails then it step back > and lets a unmatched. The other doesn't match a at first, > only if the pattern fails to match it steps back and match a. > > But don't they do eventually the same thing? > Can someone provide an example where 2 patterns yield > different results. > Perhaps this sheds some light on the matter: >>> import re >>> string = "aaaba" >>> one = re.findall(r'a?b?', string) >>> two = re.findall(r'a??b?', string) >>> print one, two Yields: ['a', 'a', 'ab', 'a', ''] ['', '', '', 'b', '', ''] -- Hope this helps, Steven -- http://mail.python.org/mailman/listinfo/python-list
