> From: bill lam > > On Fri, 07 Aug 2009, Sherlock Ric wrote: > > Obviously the best solution is to prevent the 0 fills in the first > place using one of the methods described. But if you really want to > count the non-zero numbers in each row of an array, then you could do > this: > > q: 453 32 > > 3 151 0 0 0 > > 2 2 2 2 2 > > #...@-.&0"1 q: 453 32 > > 2 5 > > > > countrows is an explicit verb that would do the same thing: > > countrows=: 3 : '# y -. 0'"1 > > countrows q: 453 32 > > 2 5 > > I guess the tacit form (ignoring "1) is #...@-.&0 is interpreted as > (#...@-.)&0 but the explicit form is #@:(-.&0)
I think I understand the idea you're trying to express but when I look at the "definition" of a tacit expression from "http://www.jsoftware.com/jwiki/Essays/Tacit%20Expressions"; it appears that all three expressions are tacit? "A tacit expression is a sequence of J operations, which can be separated from its arguments. In other words, it preserves its features when put between parentheses or assigned to a name." (#...@-.&0) 3 151 0 0 0 2 ((#...@-.)&0) 3 151 0 0 0 2 (#@:(-.&0)) 3 151 0 0 0 2 ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
