In article <th7hs8-one....@chris.zbmc.eu>, tinn...@isbd.co.uk wrote: > Can anyone suggest a simple/easy way to count how many characters have > changed in a string?
Depending on exactly how you define "changed", you're probably talking about either Hamming Distance or Levenshtein Distance. I would start with the wikipedia articles on both those topics and explore from there. There are python packages for computing many of these metrics. For example, http://pypi.python.org/pypi/python-Levenshtein/ > Is there any simpler/neater way than just a for loop running through > both strings and counting non-matching characters? If you don't care about insertions and deletions (and it sounds like you don't), then this is the way to do it. It's O(n), and you're not going to get any better than that. It's a one-liner in python: >>> s1 = 'abcdefg' >>> s2 = 'abcdekk' >>> len([x for x in zip(s1, s2) if x[0] != x[1]]) 2 But go read the wikipedia articles. Computing distance between sequences is an interesting, important, and well-studied topic. It's worth exploring a bit. -- http://mail.python.org/mailman/listinfo/python-list
