See also haukex's excellent article Building Regex Alternations Dynamically.

\w*\d*

Also note: The quoted sequence appears several times in the OPed regex example. Be aware that \d is a subset of the \w character class. This means that \w* will match any number of letters, _ (underscore) and digits and leave nothing for \d* to match. This will do no harm in the posted regex, but is a small point that should be borne in mind.

Update: Of perhaps greater significance, also note that \w*\d* will | can match nothing at all.   (s/will/can/ per suggestion of GrandFather.)   (Update: Actually, I think it's even more accurate to say that the pattern \w*\d* will always match something even if it's only the empty string. Of course, other parts of the pattern may fail to match, preventing an overall match, but that's another story. :)