Roger,
Nice! It seems there are many different approaches:
allsubsets=: #:@i.@(2&^)@# #"_1 _ ]
as=.3 :';<@(<\.)\y'
;(>:i.5) (|.@[ <@{."0 1 <\) 'abcde'
Even if the result is to be integers, It seems it is easier to start with
literals and then convert to integers later, if at all.
My next challenge is to generate all *permutations* of all subsets.
Skip
Skip Cave
Cave Consulting LLC
On Thu, Oct 24, 2019 at 1:54 PM Roger Hui <rogerhui.can...@gmail.com> wrote:
> allsubsets=: #:@i.@(2&^)@# #"_1 _ ]
> allsubsets 'abcd'
>
> d
> c
> cd
> b
> bd
> bc
> bcd
> a
> ad
> ac
> acd
> ab
> abd
> abc
> abcd
> allsubsets ;:'animal vegetable mineral'
> ┌─────────┬─────────┬───────┐
> │ │ │ │
> ├─────────┼─────────┼───────┤
> │mineral │ │ │
> ├─────────┼─────────┼───────┤
> │vegetable│ │ │
> ├─────────┼─────────┼───────┤
> │vegetable│mineral │ │
> ├─────────┼─────────┼───────┤
> │animal │ │ │
> ├─────────┼─────────┼───────┤
> │animal │mineral │ │
> ├─────────┼─────────┼───────┤
> │animal │vegetable│ │
> ├─────────┼─────────┼───────┤
> │animal │vegetable│mineral│
> └─────────┴─────────┴───────┘
>
>
>
> 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
> > > >
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