It's not a problem unless PMA says it's a problem. :-) I believe that in k, the value _2147483648 (-2^31) is used as an integer null. In so doing the integer representation becomes symmetric.
On Wed, Feb 5, 2020 at 11:09 AM Don Guinn <[email protected]> wrote: > The _. will change the array to float. Would that be a problem? > > On Wed, Feb 5, 2020, 12:03 PM Roger Hui <[email protected]> wrote: > > > 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 <[email protected]> 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 <[email protected]> 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 <[email protected]> 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 > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
