For example to match the literal string Bill but only if not followed by Gates, you could use this expression: Bill(?! Gates). (This would find Bill Clinton as well as Billy the kid, but silently ignore the other matches.)
Kui näiteks sobima peab literaalne string Bill, aga ainult juhul, kui sellele ei järgne Gates, võib kasutada sellist avaldist: Bill (?! Gates). See leiab nii väljendid Bill Clinton kui ka Billy the Kid, aga ingoneerib muid sobivusi.