comparing an array of strings

Hi All,

Having a routine that will compare two string arrays of different
sizes would be very useful to me.  Does anyone know of a routine that
previously exists that is able to compare two string arrays and return
the common elements as well as some keyword to return the differing
elements?  I could write some routine that would do it but due to my
limited knowledge of IDL it probably won't be efficient.

Thanks,
Ryan.