The OP has several patterns he wants to match - in a non-overlapping way. In particular, he wants to find out if both matches follow each other directly. There's no reason to assume the patterns cannot (partially) overlap (which is where your suggestion breaks down). Using \w and \d are two simple patterns than can match in an overlapping way. Translated into the OPs problem "check if a word character is followed by a digit, or a digit followed by a word character". "A8", "8A" and "89" are all acceptable. "&8" isn't.