I have an arbitrary matrix >:5 5 $ i.100 and want to insert a row and column of zeros between the 4th row and column respectively. So, the matrix
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 becomes 1 2 3 4 0 5 6 7 8 9 0 10 11 12 13 14 0 15 16 17 18 19 0 20 0 0 0 0 0 0 21 22 13 24 0 25 I have been trying the spread verb #^:_1 but this appears only to work on lists. I could loop through the matrix but there must be a straightforward way in J to do this. The insertions ultimately will be fairly irregular (i.e. requiring insertions of 1, 2, 3 etc rows and columns between various rows and columns. Any help on this would be greatly appreciated Thanks Bob ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
