I don't see how you exclude those matches with a regex, unless you concat all 10,000+ strings together with pipe symbols, and I doubt a regex like that would be very efficient.

One solution: Regexp::Assemble

It creates an optimized regex that checks all your strings at once. It is usually shorter and much faster than your "pipe"d regex. For example, 10,000 strings of each 5 characters were turned into a regex less than 25,000 characters long.