If I can’t remember the idiom, I look for “tap.” My favourite form is tap =: A.&i.~ !
(perm-: tap)3. NB. Same results..... 1 Cheers, Mike Sent from my iPad > On 25 May 2020, at 21:44, Skip Cave <s...@caveconsulting.com> wrote: > > perm > > 3 : 0 > > z=. i.1 0 > > for. i.y do. z=. ,/ (0 ,. 1 + z) {"2 1 \:"1 = i. 1 + {: $z end. > > : > > ,/ ({~ perm@#)"1 x comb y > > ) > > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm