Hi, I noticed that the recent numpy (1.5) implements the function in1d in set operations. Unfortunately this doesn't seem to work for structure arrays because "mergesort" isn't implemented for structure arrays. I was able to implement a quick work-around simply by adding a structure field to keep track of which list the data came from and then making this field the lowest priority in the sort. Is this worth creating a ticket for? (I don't have trac privileges to do so) Jeremy Jeremy Lewi Engineering Scientist The Intellisis Corporation jlewi@intellisis.com