If "operator" is >: there is a very easy solution: desired_result -: operand + bitmask 1
For a general monadic function, you can do as follows: desired_result -: bitmask 0&(] operator)"0 operand 1 The basic idea is what the power operator does; m&v or v&m allows you to do the same when the bitmask is an array and not a scalar. On Sun, Aug 16, 2020 at 12:45 PM Raoul Schorer <raoul.scho...@gmail.com> wrote: > Hi, > > This seems pretty trivial, but I'm stuck on how to perform conditional > application of a verb on a multidimensional array as defined by a bitmask > of the same shape as the operand array. Is there a typical idiom for that? > > For example, > > operand =. 2 2 2 $ 3 2 2 3 2 3 3 2 > > bitmask =. 2 2 2 $ 1 0 0 1 0 1 1 0 > > operator =. >: > > desired_result =. 2 2 2 $ 4 2 2 4 2 4 4 2 > > > I tried looking at the doc, but I wasn't able to formulate a nice solution. > > > Thanks! > > Raoul > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
