The "all prefixes of suffixes" (or "all suffixes of prefixes") idea was posted by Marshall Lochbaum in September 2011.
http://www.jsoftware.com/pipermail/programming/2011-September/023954.html On Thu, Oct 24, 2019 at 11:30 AM Skip Cave <s...@caveconsulting.com> wrote: > I find R. E. Boss' function quite useful in many instances. I call it "all > sets". Is this a standard idiom in J? Is there a more efficient > construction that does this? Is there a primitive that does this? > > as=.3 :';<@(<\.)\y' NB. All Sets > > as i.5 > > │0│0 1│1│0 1 2│1 2│2│0 1 2 3│1 2 3│2 3│3│0 1 2 3 4│1 2 3 4│2 3 4│3 4│4│ > > > Skip > > > > On Thu, Oct 24, 2019 at 12:30 PM R.E. Boss <r.e.b...@outlook.com> wrote: > > > Obviously the squares >2018 don't play any role whatsoever, so you can > > restrict yourself to %:2018 > > > > >a#~2018=>+/ each a=.;<@(<\.)\2^~i.>.%:2018 > > 49 64 81 100 121 144 169 196 225 256 289 324 > > > > R.E. Boss > > > > > > > -----Oorspronkelijk bericht----- > > > Van: Programming <programming-boun...@forums.jsoftware.com> > > > Namens Skip Cave > > > Verzonden: donderdag 24 oktober 2019 19:12 > > > Aan: programm...@jsoftware.com > > > Onderwerp: Re: [Jprogramming] Quora problem > > > > > > To me it seems that R. E. Boss provided the simplest approach. > > > Don't know about efficiency, but the results appear instantly: > > > > > > >a#~2018=>+/ each a=.;<@(<\.)\2^~i.100 > > > > > > 49 64 81 100 121 144 169 196 225 256 289 324 > > > > > > 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 > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
