Question

In my work I have with great results used approximate string matching algorithms such as Damerau–Levenshtein distance to make my code less vulnerable to spelling mistakes.

Now I have a need to match strings against simple regular expressions such TV Schedule for \d\d (Jan|Feb|Mar|...). This means that the string TV Schedule for 10 Jan should return 0 while T Schedule for 10. Jan should return 2.

This could be done by generating all strings in the regex (in this case 100×12) and find the best match, but that doesn’t seam practical.

Do you have any ideas how to do this effectively?

Answer 1

I found the TRE library, which seems to be able to do exactly fuzzy matching of regular expressions. Example: http://hackerboss.com/approximate-regex-matching-in-python/
It only supports insertion, deletion and substitution though. No transposition. But I guess that works ok.

I tried the accompanying agrep tool with the regexp on the following file:

TV Schedule for 10Jan
TVSchedule for Jan 10
T Schedule for 10 Jan 2010
TV Schedule for 10 March
Tv plan for March

and got

$ agrep -s -E 100 '^TV Schedule for \d\d (Jan|Feb|Mar)$' filename
1:TV Schedule for 10Jan
8:TVSchedule for Jan 10
7:T Schedule for 10 Jan 2010
3:TV Schedule for 10 March
15:Tv plan for March

Thanks a lot for all your suggestions.