In general, if you want to apply u along a group of n of axes: axis=: 2 : 0 u"(#n)@(n&|:) )
This is I believe very close to the axis operator in APL if you are familiar with it: ]m=: i.2 3 4 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 < axis 0 m +----+----+-----+-----+ |0 12|1 13|2 14 |3 15 | +----+----+-----+-----+ |4 16|5 17|6 18 |7 19 | +----+----+-----+-----+ |8 20|9 21|10 22|11 23| +----+----+-----+-----+ < axis 1 m +--------+--------+--------+--------+ |0 4 8 |1 5 9 |2 6 10 |3 7 11 | +--------+--------+--------+--------+ |12 16 20|13 17 21|14 18 22|15 19 23| +--------+--------+--------+--------+ < axis 2 m +-----------+-----------+-----------+ |0 1 2 3 |4 5 6 7 |8 9 10 11 | +-----------+-----------+-----------+ |12 13 14 15|16 17 18 19|20 21 22 23| +-----------+-----------+-----------+ < axis 0 1 m +--------+--------+--------+--------+ | 0 4 8| 1 5 9| 2 6 10| 3 7 11| |12 16 20|13 17 21|14 18 22|15 19 23| +--------+--------+--------+--------+ < axis 0 2 m +-----------+-----------+-----------+ | 0 1 2 3| 4 5 6 7| 8 9 10 11| |12 13 14 15|16 17 18 19|20 21 22 23| +-----------+-----------+-----------+ < axis 1 0 m +----+----+-----+-----+ |0 12|1 13| 2 14| 3 15| |4 16|5 17| 6 18| 7 19| |8 20|9 21|10 22|11 23| +----+----+-----+-----+ In particular, you want < axis 0 i.5 2 +---------+---------+ |0 2 4 6 8|1 3 5 7 9| +---------+---------+ Cheers, Louis > On 25 Aug 2017, at 05:54, bill lam <[email protected]> wrote: > > <"1 |: B > +-------+-------+ > |0 2 4 6|1 3 5 7| > +-------+-------+ > > if this is not what you wanted, then try > > <@,."1 |: B > +-+-+ > |0|1| > |2|3| > |4|5| > |6|7| > +-+-+ > > > -- > regards, > ==================================================== > GPG key 1024D/4434BAB3 2008-08-24 > gpg --keyserver subkeys.pgp.net --recv-keys 4434BAB3 > gpg --keyserver subkeys.pgp.net --armor --export 4434BAB3 > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
