Harvey, To elaborate on what Dan said, it's important to note that each of the boxes in the boxed-columns is itself a two-axis array.
,. <"1 a +---------+ |0 1 2 3 | +---------+ |4 5 6 7 | +---------+ |8 9 10 11| +---------+ $&.> a2 +---+---+---+---+ |3 1|3 1|3 1|3 1| +---+---+---+---+ A simpler boxing of the columns of (a) would have each column result in a simple list of the values, like this: ]ca=. <"1 |: a +-----+-----+------+------+ |0 4 8|1 5 9|2 6 10|3 7 11| +-----+-----+------+------+ $&.> ca +-+-+-+-+ |3|3|3|3| +-+-+-+-+ To take a two-axis noun and carry both axes into the result, either the contents of the boxes or the boxes themselves must have rank two. ,. <"1 a +---------+ |0 1 2 3 | +---------+ |4 5 6 7 | +---------+ |8 9 10 11| +---------+ $ ,. <"1 a 3 1 -- Tracy ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
