thanks. As usual J proves to be far more flexible than hoped. Kip's last example was what I was looking for, but I will need Dan's examples for some other problems.
During my trials, I had it locked in my head that '[: is a suicide verb... so how do I force a verb to be monadic'. NB. replace any column a (<a:;1)}&.> b NB. replace any row a (<1)}&.> b --Steven ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
