In the context of the ICE modeling challenge I came up with a small compound to get the intersection of 2 integer arrays, for example [1,5,7,9] and [2,4,5,7,12] will give [5,7].
You can see the ICE Tree for it in this thread. (Moderator edit - ...or below - HB)
Just beware it will build arrays of the size of the maximum integer value, so might not be the best choice if you want to intersect arrays like [ 12323, 2350924 ]
Claude
Moderator edit: I've hidden the URL behind "this thread" and added a direct [img] link to the image... - HB