First off, stop flooding the CB each time you post a question, people will see them and reply when they are ready. See the Perlmonks FAQ and How do I post a question effectively?.

Secondly, did you Super Search before posting? How can I find the union/difference/intersection of two arrays? from Categorized Questions and Answers seems like a good place to start right? or perhaps looking at perldoc? How do I compute the difference of two arrays? How do I compute the intersection of two arrays? from prelfaq4 is another reference point.

A similar if not exactly the same question was asked here a few days ago.

Martin