Using RE’s and Henry’s suggestions, a slight generalisation to your #3 …
as2=: ;(#\ <@<"1@([\) ]) ‘abcdef'
Rob
> On 26 Oct 2019, at 7:36 am, Skip Cave <s...@caveconsulting.com> wrote:
>
> 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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