Roger: thanks. Selecting an unlikely value is no problem: the real problem is when you want to do data transformations in the presence of missing data: in this case what's needed is for missing values to persist. That's why I liked expressions like 1 2 3 + 1 _. 3 giving 2 _. 6.
As to slowdowns, point taken: but I'm using J here as a way to prepare a dataset for input to a statistics package, so the work won't be repeated often, and I may be willing to put up with slow processing. (Or maybe not, once I see how slow it really is).
Still, could I ask again: what are the rules for combining numbers with Indeterminate?
------------------------ Philip A. Viton City Planning, Ohio State University 275 West Woodruff Avenue, Columbus OH 43210 [EMAIL PROTECTED] ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
