I've just finished a rather complicated bit of data munging, which required me to aggregate numeric data in various ways: this is duck-soup for J, given its ability to group subsets of the data into boxes, and then operate on the boxes.
But what made the task truly difficult was the handling of missing data. The problem of keeping track of which items were missing and which were "real" almost convinces me that J is not an appropriate tool for this kind of task. R is one language that does have built-in facilities for missing data, but I don't think R has J's boxing power, which was needed here.
Does anyone have any ideas about how J might be coerced into being more effective here? Using _ (infinity) for missing data *almost* works (at least for non-negative data), except that 0 = _ % _ ; and 0 is a possible "real" value. I suppose one could write substitute verbs for the needed arithmetic operators, and even do element-by-element processing there; but this sort of negates the value of J in the first place.
------------------------ 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
