> Wow. Just when I think I'm starting to get proficient in the language... > M (4 $. [: $. =) 6 32 58
One might never stop learning, or relearning J ;) [Jgeneral] (i. 2 3) i. 4 NB. you know what i mean... how do iget it to work?! Dan Bron http://www.jsoftware.com/pipermail/general/2007-May/029887.html On Fri, Nov 13, 2020 at 1:26 PM Devon McCormick <[email protected]> wrote: > > Wow. Just when I think I'm starting to get proficient in the language... > M (4 $. [: $. =) 6 32 58 > 0 1 1 > 1 2 2 > 2 3 3 > > This sparse array approach behaves differently from my proposal for an edge > condition (lookup not found): > M (4 $. [: $. ="_ 0~) 99 NB. Empty result for "not found" > M (([: $ [) #: ] i.~ [: , [) 99 NB. versus potentially misleading > result. > 0 0 0 > > I stumbled on this in my attempt to accommodate an array right argument > with Ric's solution: > M ([: 4&$.@:$. ="_ 0~) 2 3$6 7 8 32 58 59 > 0 1 1 0 0 > 0 1 2 0 1 > 0 1 3 0 2 > 1 2 2 1 0 > 2 3 3 1 1 > 2 3 4 1 2 > > This appears to indicate the indexes into the left argument in the first 3 > columns and the indexes of the corresponding items on the right in the last > two columns (because a 3D argument on the left and a 2D argument on the > right). > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
