Something confused me on the subject page. The shift right is only for a vector and behaves differently for a matrix.
|.!.f says it will shift right 1, but when I tried it on a matrix, it shifts down. ]a=:4 4 $ 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 |.!._1 a _1 _1 _1 _1 1 0 0 0 0 1 0 0 0 0 1 0 same as: _1 |.!._1 a _1 _1 _1 _1 1 0 0 0 0 1 0 0 0 0 1 0 For it to shift right it needs to identify the second axis: 0 _1|.!._1 a _1 1 0 0 _1 0 1 0 _1 0 0 1 _1 0 0 0 Anyway just thought to mention it since, at least for newbies, they might find it confusing. ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm