W w : w = weeks. W weeks preceded by a leading zero if smaller than 10
D d : d = days. D days preceded by a leading zero if smaller than 10
G g : g = Military Hours: G hours preceded by a leading zero if smaller than 10
H h : h = Civilian Hours: H hours preceded by a leading zero...
m : m = minutes
s : s = seconds

(w|W)(?=b)|(d|D)(?=b)|(h|H|g|G)(?=b)|(m)(?=b)|(s)(?=b)

(w|W) //match upper or lower W
(?=b) //positive lookahead only match if not apart of a word boundary

Format("w Weeks, D days, h:m:s");
//returns 7 Weeks, 04 days, 10:01:05
Format("[w] weeks [d] days H:m:s");
//returns [7] weeks [4] days 10:01:05
Format("w Weeks D days, h:m:s");
//returns 7 07eeks 04 4ays, 10:01:05