Wow! Great answers. I didn't think this could be done without control statements. By now I should know that J's powerful set of primitives can implement most any algorithm without requiring looping statements.
Mike Day's sharp eye spotted the fact that my data was derived from an infix sliding-window boxing of an unboxed vector. Mike's step-by-step set of verb definitions helped greatly in understanding what was going on. Raul's monster tacit verb is probably the most complex tacit expression I have ever tried to analyze. His de-construction of the verb helped in my understanding, but my tacit skills are still a way from being able to create something like this on my own. Hopefully, my study of this function will improve my tacit skills. Thanks for all your help, Skip ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
