Thanks Raul, Nothing much to understand, really. I liked the simplicity of your suggestion: (0 2 |: _2 ]\ ]) i. 6 3
So I thought that if I just reshape my 2M x N matrix into an M x 2 x N then I can apply your idea! Which is all my reshape2s verb does, i.e. reshape a 2N x into an M x 2 X N I am sure that there are more elegant, J-like ways to do it, but hey, it works. (I am still studying the other suggestions) Regards AG On 21 November 2012 23:38, Raul Miller <[email protected]> wrote: > I do not understand the question, but here's something that operates on i. > 6 3: > > (0 2 |: _2 ]\ ]) i. 6 3 > > Note that this is almost identical to Roger Hui's suggestion. > > -- > Raul > > On Wed, Nov 21, 2012 at 1:12 PM, Alex Giannakopoulos > <[email protected]> wrote: > > Well, I'm having a bit of trouble getting my head around "key", I'll keep > > at it though... > > However I was inspired by Raul's solution to come up with something that > > worked and I understood. > > Well, sort of understood anyway, why does the evenoddrows verb not need > to > > be (0 2 |: @ reshape2s) ? > > > > reshape2s =. ;$~(2%~0{$),2,1{$ > > evenoddrows =. 0 2 |: reshape2s > > evenoddrows i. 8 4 > > 0 1 2 3 > > 8 9 10 11 > > 16 17 18 19 > > 24 25 26 27 > > > > 4 5 6 7 > > 12 13 14 15 > > 20 21 22 23 > > 28 29 30 31 > > > > Hope that's not too inefficient > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
