Matching two strings allowing a single swap

Question

I am running a fuzzy match algorithm, that allows two strings to have a single difference by Levenshtein metrics. But there is a frequent misprint when two consequent letters are swapped:

Jonathan -> Joanthan

professional -> profesisonal

but those differencies give 2 by Levenshtein. How do I match those differencies also?

Answer 1

What you describe is the Damerau–Levenshtein distance. It's the Levenshtein distance including adjacent transpositions.