Careful: 0*_ and _*0 do not leave _ untouched: both return 0. (Likewise for __ .)
Another alternative is to use an associated boolean array whose 1s indicate non-null values. On Wed, Feb 5, 2020 at 8:50 AM PMA <armst...@eskimo.com> wrote: > Aha, so arithmetic functions will just leave it as-is. Just right! > > On 02/04/2020 08:22 PM, Devon McCormick wrote: > > You might also consider "_" (infinity) or "__" (negative infinity). > > > > On Tue, Feb 4, 2020 at 8:19 PM PMA <armst...@eskimo.com> wrote: > > > >> Thanks, Roger, I'll look into this! > >> > >> On 02/04/2020 04:33 PM, Roger Hui wrote: > >>> You could try using _. (aka NaN aka indeterminate). But read > >>> http://code.jsoftware.com/wiki/Essays/Indeterminate first. > >>> > >>> > >>> > >>> On Tue, Feb 4, 2020 at 12:46 PM PMA <armst...@eskimo.com> wrote: > >>> > >>>> J gurus -- > >>>> I have a numerical array in which some positions > >>>> need to display either 0 (a literal zero) OR > >>>> nothing at (be empty). Is this possible somehow > >>>> using the NULL value, with math functions simply > >>>> bypassing it? > >>>> Thanks in advance, > >>>> Peter A > >>>> ---------------------------------------------------------------------- > >>>> 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 > >> > > > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
