According to the documentation on re.sub(), it replaces the leftmost matching pattern.
However, I want to replace the *longest* matching pattern, which is not necessarily the leftmost match. Any suggestions? I'm working with IPv6 CIDR strings, and I want to replace the longest match of "(0000:|0000$)+" with ":". But when I use re.sub() it replaces the leftmost match, even if there is a longer match later in the string. I'm also looking for a regexp that will remove leading zeroes in each four-digit group, but will leave a single zero if the group was all zeroes. Thanks! -- John Gordon A is for Amy, who fell down the stairs gor...@panix.com B is for Basil, assaulted by bears -- Edward Gorey, "The Gashlycrumb Tinies" -- http://mail.python.org/mailman/listinfo/python-list