"Roger Stafford" wrote in message <email@example.com>... > You shouldn't give up so quickly, Petra. The answer you gave was correct - for the positions in 'a'. - - - - - - - Oops! I was hasty in reading your answer. As Nassar indicates, the 8 is incorrect. However, it is convenient to use 'ismember' if you want to find both the like numbers and their position.