I like the hash-lookup approach, but nikolay seems to want to exclude digit groups rather than just the explicit  "2" substring. (I admit this is a bit difficult to divine given the pseudo-regex provided in the OP.) So, a substring like  "23-x" in the input string would become  "x-23" in the output string. Again, my guess is that this is not what the OPer wants.

Give a man a fish:  <%-{-{-{-<

In reply to Re^2: RegExp: words exceptions list similar to characters' one. by AnomalousMonk
in thread [CLOSED] RegExp: words excepstions list similar to characters' one. by nikolay

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