Hi Ron

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"Ron" == Ron Adam writes: Ron> I was thinking of something a bit more light weight.

Ah, now we got to what you actually want to do :-) Ron> For more complex stuff I think the 're' module already does pretty Ron> much what you are describing. It may even already take advantage of Ron> the algorithms you referred to. If not, that would be an important Ron> improvement to the re module. :-) Yes, that would make a good SoC project. But as you say it may already be done that way. Ron> The use case I had in mind was to find starting and ending delimiters. Ron> And to avoid the following type of awkward code. (This would work for Ron> finding other things as well of course.) start = 0 while start < len(s): i1 = s.find('{', start) if i1 == -1: i1 = len(s) i2 = s.find('}', start) if i2 == -1: i2 = len(s) # etc... for as many search terms as you have... # or use a loop to locate each one. start = min(i1, i2) if start == len(s): break ... # do something with s[start] ... Ron> That works but it has to go through the string once for each item. It's worse than that. _Each time around the loop_ it tests all candidates against all of the remaining text. Imagine matching L patterns that were each 'a' * M against a text of 'a' * N. You're going to do (roughly) O(N * L * M) comparisons, using naive string matching. You could completely drop patterns that have already returned -1. You can short-circuit a loop if you ever got a 0 index back. Sorry if this seems picky - I guess you're just writing quick pseudo-code. Ron> Of course I would use 're' for anything more complex than a few fixed Ron> length terms. Yes. It depends partly on what you want back. You could write a super-fast iterator based on A&C that told you everything you need to know, with guaranteed linear worst case behavior, but that seems like overkill here (and it may be in re, as you say). Ron> If the function returns something other than a simple index, then I Ron> think it will need to be a new function or method and not just an Ron> alteration of str.index and str.find. In that case it may also need a Ron> PEP. Be my guest :-) Regards, Terry