Ooh! A performance thread! This function is about one-third better than str_join. def str_join2(iters): has = {0:1,1:1,2:1,3:1,4:1,5:1,6:1,7:1,8:1,9:1}.has_key for i in iters: "".join([x for x in '(123)/456-7890' if has(x)]) :-) -- Skip Montanaro (skip at pobox.com) (847)971-7098