Yes, Roger’s string-based version avoided my need to remove spaces with boxing.
FWIW, this approach just maps its inputs for later formatting:
(it looks awful on this iPad; hope it’s ok on receipt)
to=. (<@ (10 #.inv *:))"0 i.10
h =: ;@:{ &to
h each^:(i.5)<9
+-+---+-----+---------+-------------+
|9|8 1|6 4 1|3 6 1 6 1|9 3 6 1 3 6 1|
+-+---+-----+---------+-------------+
10x #. every h each^:(i.5)<9
9 81 641 36161 9361361
...or even
({&'0123456789')every h each^:(i.5)<9
9
81
641
36161
9361361
Lots of ways to skin this cat.
BTW, Alan Turing appears in Ian McEwan’s new novel, “Machines like Me”
Cheers,
Mike
Sent from my iPad
> On 14 May 2019, at 11:48, R.E. Boss <[email protected]> wrote:
>
> The string approach seems more efficient in the long run, I guess.
> The human eye makes no difference between the string and the corresponding
> number, so why would I?
>
> I prefer Hui's solution with a slight amendment on f and preprocessing the
> input number:
>
> f=: ; @: (*:&.".&.>)
> f^:(i.10) ": 9
>
> R.E. Boss
>
>
>> -----Oorspronkelijk bericht-----
>> Van: Programming <[email protected]>
>> Namens Ben Gorte
>> Verzonden: dinsdag 14 mei 2019 03:40
>> Aan: [email protected]
>> Onderwerp: Re: [Jprogramming] Seqfan problem
>>
>> I can make it a few characters shorter and avoid the logarithm, but the main
>> idea is still the same:
>>
>>
>> g =: (#.~10x^(1+>&9))@:*:@:(10&#.^:_1)
>>
>> ,.g^:(<10) 9
>>
>> 9
>>
>> 81
>>
>> 641
>>
>> 36161
>>
>> 9361361
>>
>> 8193619361
>>
>> 641819361819361
>>
>> 36161641819361641819361
>>
>> 93613613616164181936136161641819361
>>
>> 8193619361936136136161641819361936136136161641819361
>>
>>
>> I think the difference between R.E.'s/my idea at one side, and Mike's or
>> Roger's at the other, is that we actually compute the numbers of the
>> sequence, whereas they 'only' generate the strings. Or is that futile?
>>
>>
>> Greetings
>>
>> Ben
>>
>> On Tue, May 14, 2019 at 12:07 AM Roger Hui <[email protected]>
>> wrote:
>>
>>> f=: ; @: (*:&.".&.>) @: ":
>>>
>>> f 9
>>> 81
>>> f f 9
>>> 641
>>> f f f 9
>>> 36161
>>>
>>> f^:(i.10) 9
>>> |domain error
>>> | f^:(i.10)9
>>>
>>> This last runs afoul because of f^:0]9 which has a numeric result and
>>> can not be mixed with the other f^:n]9. It can be fixed by
>>> preapplication of
>>> ": or by starting with '9', or by not doing f^:0 of course.
>>>
>>> f^:(i.10) ": 9
>>> 9
>>> 81
>>> 641
>>> 36161
>>> 9361361
>>> 8193619361
>>> 641819361819361
>>> 36161641819361641819361
>>> 93613613616164181936136161641819361
>>> 8193619361936136136161641819361936136136161641819361
>>>
>>>> On Mon, May 13, 2019 at 2:48 AM R.E. Boss <[email protected]>
>>> wrote:
>>>
>>>> Was wrong subject. My mailing is getting rusty too.
>>>>
>>>>
>>>> R.E. Boss
>>>>
>>>>
>>>>> -----Oorspronkelijk bericht-----
>>>>> Van: Programming <[email protected]>
>>>>> Namens R.E. Boss
>>>>> Verzonden: maandag 13 mei 2019 11:07
>>>>> Aan: [email protected]
>>>>> Onderwerp: Re: [Jprogramming] JELM - Extreme Learning Machine in J
>>>>>
>>>>> It took me more time than expected to produce the sequence of
>>>>> numbers
>>> in
>>>>> J:
>>>>>
>>>>> (from Seqfan Mailing list - http://list.seqfan.eu/)
>>>>>> Beginning with a two-digit square, successively replace each
>>>>>> digit with its square, then repeat.
>>>>>>
>>>>>> For example,
>>>>>> 9
>>>>>> 81
>>>>>> 641
>>>>>> 36161
>>>>>> 9361361
>>>>>> 8193619361
>>>>>> 641819361819361
>>>>>> 36161641819361641819361
>>>>>> 93613613616164181936136161641819361
>>>>>
>>>>> ((]#.~ 10x^10>:@<.@^.]) *:@(10&#.^:_1))^:(i.10)9
>>>>> 9 81 641 36161 9361361 8193619361 641819361819361
>>>>> 36161641819361641819361 93613613616164181936136161641819361
>>>>> 8193619361936136136161641819361936136136161641819361
>>>>>
>>>>> Curious about other, more elegant solutions, since my J is getting
>>> rusty.
>>>>>
>>>>>
>>>>> R.E. Boss
>>>>> ------------------------------------------------------------------
>>>>> ---- 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
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
