What I would really like is for I. to return a _1 whenever there is no 1 in the match array, since there cannot be a negative index:
I.5=1 2 3 4 6 4 3 4 4 6 7 6 4 8 10 Idot 5=1 2 3 4 6 4 3 4 4 6 7 6 _1 ]m=.|:1 2 3 4,. 2 3 4 5,. 5 4 3 2 ,. 2 3 5 4 1 2 3 4 2 3 4 5 5 4 3 2 2 3 5 4 5=m 0 0 0 0 0 0 0 1 1 0 0 0 0 0 1 0 ,Idot .5=m _1 3 0 2 Can a verb Idot be designed, that does this? Skip Cave Cave Consulting LLC On Sun, Jan 13, 2019 at 2:41 PM Henry Rich <[email protected]> wrote: > Right. Prefer (I.@:= ,) to I.@,@:= since it uses special code. > > Henry Rich > > On 1/13/2019 2:54 PM, 'Mike Day' via Programming wrote: > > You often see this sort of thing, returning pairs of indices of all > occurrences: > > > > 5 ($@] #.inv I.@,@:=) |: 1 2 3 4,. 2 3 4 5,. 5 4 3 2 ,. 2 3 5 4 > > 1 3 > > 2 0 > > 3 2 > > > > You can obviously get the row indices using {:”1 or some such, and you > can of course make the bracketed code a named dyadic verb, > > > > Cheers, > > > > Mike > > > > > > Sent from my iPad > > > >> On 13 Jan 2019, at 17:55, 'Skip Cave' via Programming < > [email protected]> wrote: > >> > >> I know I can find the location (index) of a specific integer in a > vector of > >> integers using I. > >> > >> I.5=1 2 3 4 5 4 3 4 5 6 5 6 > >> > >> 4 8 10 > >> > >> > >> So I want to find the row index of a specific integer in an array of > >> integers: > >> > >> |:1 2 3 4,. 2 3 4 5,. 5 4 3 2 ,. 2 3 5 4 > >> > >> 1 2 3 4 > >> > >> 2 3 4 5 > >> > >> 5 4 3 2 > >> > >> 2 3 5 4 > >> > >> 5=|:1 2 3 4,. 2 3 4 5,. 5 4 3 2 ,. 2 3 5 4 > >> > >> 0 0 0 0 > >> > >> 0 0 0 1 > >> > >> 1 0 0 0 > >> > >> 0 0 1 0 > >> > >> ,I. 5=|:1 2 3 4,. 2 3 4 5,. 5 4 3 2 ,. 2 3 5 4 > >> > >> 0 3 0 2 > >> > >> > >> The first zero indicates that there is no 5 in the first row. The second > >> zero gives the index of the 5 in the third row. How can I tell whether > the > >> zero is an index, or a null indicator? > >> > >> Skip > >> ---------------------------------------------------------------------- > >> For information about J forums see http://www.jsoftware.com/forums.htm > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > > > --- > This email has been checked for viruses by AVG. > https://www.avg.com > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
