I'm afraid I don't understand your question. But, as usual, that won't stop me <g>!

You can factor out bits of a regular expression, and pre-compile them using the qr() operator:

 my $H = qr{abjdk|adfkj};
 if ($thisstring =~ $H) {
  # do stuff
 }
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If this isn't what you mean, please clarify.