tuoinside

Hello all! I am looking for a quick script that will examine a string of numbers, and output consecutive numbers that are not present in a given range. IE. string = 1, 3, 4, 5, 9, 10, 12 Returns = 2, 6, 7, 8, 11, 14 for range 1-14 etc. Could this be done with a match or strpos function? Any help would be greatly appreciated!!! Thanks in advance,