Re: [Jprogramming] Selective verb application
Oh, and as you've probably noticed, } and { could be used here, also
(perhaps without using the rank conjunction, if the underlying verb
had a servicable rank).
Thanks,
--
Raul
On Thu, Jan 16, 2020 at 9:07 AM Raul Miller wrote:
>
> Certainly.
>
> But I would be inclined to swap left and right arguments on you (to
> follow the pattern we saw in Roger Hui's post).
>
> Some rather straightforward examples uses ^: or @. as their core
> mechanism, and rank to spread the operation across the arguments.
>
> This could be done either explicitly or tacitly -- it's that
> straightforward -- though if you get into additional constraints that
> could change the playing field.
>
> Does this give you enough clues to see your way forward? Or are you
> wanting to see canned implementations? (Be aware that canned
> implementation get into questions which you've not yet addressed, like
> "what rank"?)
>
> Thanks,
>
> --
> Raul
>
> On Thu, Jan 16, 2020 at 3:44 AM Skip Cave wrote:
> >
> > I'm thinking of something along the lines of # (copy)
> >
> > 1 1 1 0 1 0 0 1 0 1 # i.10
> >
> > 0 1 2 4 7 9
> >
> >
> > Only "apply" uses a boolean left argument to define which elements on the
> > right are affected by the verb:
> >
> >
> > 1 1 1 0 1 0 0 1 0 1 (apply -.) 1 1 1 1 1 1 1 1 1 1
> >
> > 0 0 0 1 0 1 1 0 1 0
> >
> > 1 1 1 0 1 0 0 1 0 1 (apply 2&+) 1 1 1 1 1 1 1 1 1 1
> >
> > 3 3 3 1 3 1 1 3 1 3
> >
> > 1 1 1 0 1 0 0 1 0 1 (apply 2&^~) i.10
> >
> > 0 1 4 3 16 5 6 49 8 81
> >
> > Is this possible?
> >
> > Skip Cave
> > Cave Consulting LLC
> >
> >
> > On Thu, Jan 16, 2020 at 2:08 AM Arnab Chakraborty wrote:
> >
> > > My first idea was to use ^: . But I am unable to get a solution. None of
> > > the posted solutions use ^: either. Just wondering whether ^: can help
> > > here.
> > >
> > > On Thu, 16 Jan 2020, 12:36 'robert therriault' via Programming, <
> > > programm...@jsoftware.com> wrote:
> > >
> > > > It is too late, considering the result is not the one that you
> > > > requested!
> > > >
> > > > Anyway I would use a numerical approach something like the incorrect one
> > > > that I just posted.
> > > >
> > > > Sheepishly - Cheers, bob
> > > >
> > > > > On Jan 15, 2020, at 23:03, 'robert therriault' via Programming <
> > > > programm...@jsoftware.com> wrote:
> > > > >
> > > > > Hi Skip,
> > > > >
> > > > > A late snowy night silly approach
> > > > >
> > > > >]a=.20#1
> > > > > 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
> > > > > f1=. *@(3&|)@:i.@:# NB. mod 3 non-zeros
> > > > > f1 a
> > > > > 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1
> > > > > f2=. -.@*@(2&|)@:i.@:# NB. mod 2 zeros
> > > > > f2 a
> > > > > 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0
> > > > > (f1 *: f2) a NB. Not-And fork
> > > > > 1 1 0 1 0 1 1 1 0 1 0 1 1 1 0 1 0 1 1 1
> > > > > f=. f1 *: f2 NB. requested result
> > > > > f a
> > > > > 1 1 0 1 0 1 1 1 0 1 0 1 1 1 0 1 0 1 1 1
> > > > >
> > > > > Cheers, bob
> > > > >
> > > > >
> > > > >> On Jan 15, 2020, at 22:29, Skip Cave wrote:
> > > > >>
> > > > >> ]a=.20#1
> > > > >
> > > > > --
> > > > > 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
Re: [Jprogramming] Selective verb application
a generic approach,
([: (0 ~: 3 | i.@:#@{.)`]} ] ,:~ >: ) i.20
1 1 2 4 4 5 7 7 8 10 10 11 13 13 14 16 16 17 19 19
can be turned into conjunction where u = verb you want to apply, n is the
interval
fornth1 =: 2 : '([: (0 ~: n | i.@:#@{.)`]} ] ,:~ u )'
except your desired result does not actually literally apply just nth element.
Rather, in your example, the 0th and 2nd indexes are repeatedly incremented.
If instead just the nth elements are to be processed then the conjunction is:
fornth =: 2 : '([: ((n-1) = n | i.@:#@{.)`]} ] ,: u )'
>: fornth 3 i.20
0 1 3 3 4 6 6 7 9 9 10 12 12 13 15 15 16 18 18 19
>: fornth 3 i.20
On Wednesday, January 15, 2020, 09:30:38 p.m. EST, Skip Cave
wrote:
How does one apply a monadic verb repetitively to every nth element of a
one1-dimentional array?
For example:
]a=.i.20
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
n=.3
NB. Design u to increment every nth integer in a:
u=.??:http://www.jsoftware.com/forums.htm
--
For information about J forums see http://www.jsoftware.com/forums.htm
Re: [Jprogramming] Selective verb application
Certainly. But I would be inclined to swap left and right arguments on you (to follow the pattern we saw in Roger Hui's post). Some rather straightforward examples uses ^: or @. as their core mechanism, and rank to spread the operation across the arguments. This could be done either explicitly or tacitly -- it's that straightforward -- though if you get into additional constraints that could change the playing field. Does this give you enough clues to see your way forward? Or are you wanting to see canned implementations? (Be aware that canned implementation get into questions which you've not yet addressed, like "what rank"?) Thanks, -- Raul On Thu, Jan 16, 2020 at 3:44 AM Skip Cave wrote: > > I'm thinking of something along the lines of # (copy) > > 1 1 1 0 1 0 0 1 0 1 # i.10 > > 0 1 2 4 7 9 > > > Only "apply" uses a boolean left argument to define which elements on the > right are affected by the verb: > > > 1 1 1 0 1 0 0 1 0 1 (apply -.) 1 1 1 1 1 1 1 1 1 1 > > 0 0 0 1 0 1 1 0 1 0 > > 1 1 1 0 1 0 0 1 0 1 (apply 2&+) 1 1 1 1 1 1 1 1 1 1 > > 3 3 3 1 3 1 1 3 1 3 > > 1 1 1 0 1 0 0 1 0 1 (apply 2&^~) i.10 > > 0 1 4 3 16 5 6 49 8 81 > > Is this possible? > > Skip Cave > Cave Consulting LLC > > > On Thu, Jan 16, 2020 at 2:08 AM Arnab Chakraborty wrote: > > > My first idea was to use ^: . But I am unable to get a solution. None of > > the posted solutions use ^: either. Just wondering whether ^: can help > > here. > > > > On Thu, 16 Jan 2020, 12:36 'robert therriault' via Programming, < > > programm...@jsoftware.com> wrote: > > > > > It is too late, considering the result is not the one that you requested! > > > > > > Anyway I would use a numerical approach something like the incorrect one > > > that I just posted. > > > > > > Sheepishly - Cheers, bob > > > > > > > On Jan 15, 2020, at 23:03, 'robert therriault' via Programming < > > > programm...@jsoftware.com> wrote: > > > > > > > > Hi Skip, > > > > > > > > A late snowy night silly approach > > > > > > > >]a=.20#1 > > > > 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 > > > > f1=. *@(3&|)@:i.@:# NB. mod 3 non-zeros > > > > f1 a > > > > 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 > > > > f2=. -.@*@(2&|)@:i.@:# NB. mod 2 zeros > > > > f2 a > > > > 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 > > > > (f1 *: f2) a NB. Not-And fork > > > > 1 1 0 1 0 1 1 1 0 1 0 1 1 1 0 1 0 1 1 1 > > > > f=. f1 *: f2 NB. requested result > > > > f a > > > > 1 1 0 1 0 1 1 1 0 1 0 1 1 1 0 1 0 1 1 1 > > > > > > > > Cheers, bob > > > > > > > > > > > >> On Jan 15, 2020, at 22:29, Skip Cave wrote: > > > >> > > > >> ]a=.20#1 > > > > > > > > -- > > > > 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
Re: [Jprogramming] Selective verb application
Bits are a domain where identity values tend to be easy to find. And, of course, the approach Roger Hui mentioned works great for this example: Operation: ~: Identity value: 0 Mask: 0=3|i.@# a=:20#1 (~: 0=3|i.@#) a 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 FYI, -- Raul On Thu, Jan 16, 2020 at 1:30 AM Skip Cave wrote: > > Suppose I want to invert every 3rd binary bit, then every second bit where > f is -. (selective not): > > ]a=.20#1 > > 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 > > ]b=.3 f a > > 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 > > ]c .2 f b > > 1 1 0 0 0 1 1 1 0 0 0 1 1 1 0 0 0 1 1 1 > > > How to define f? > > > Skip > > > > > > On Wed, Jan 15, 2020 at 8:30 PM Skip Cave wrote: > > > How does one apply a monadic verb repetitively to every nth element of a > > one1-dimentional array? > > > > For example: > > > >]a=.i.20 > > 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 > > n=.3 > > > > NB. Design u to increment every nth integer in a: > > > > > > u=.??: > n u a > > 1 1 2 4 4 5 7 7 8 10 10 11 13 13 14 16 16 17 19 19 > > > -- > For information about J forums see http://www.jsoftware.com/forums.htm -- For information about J forums see http://www.jsoftware.com/forums.htm
Re: [Jprogramming] Selective verb application
f=: 4 :',(-.@{. 0}])&.|: (-x)[\y'
3 f a
0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 0
2 f 3 f a
1 1 0 0 0 1 1 1 0 0 0 1 1 1 0 0 0 1 1 1 1 0
R.E. Boss
> -Oorspronkelijk bericht-
> Van: Programming
> Namens Skip Cave
> Verzonden: donderdag 16 januari 2020 07:30
> Aan: programm...@jsoftware.com
> Onderwerp: Re: [Jprogramming] Selective verb application
>
> Suppose I want to invert every 3rd binary bit, then every second bit where f
> is -. (selective not):
>
> ]a=.20#1
>
> 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
>
> ]b=.3 f a
>
> 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1
>
> ]c .2 f b
>
> 1 1 0 0 0 1 1 1 0 0 0 1 1 1 0 0 0 1 1 1
>
>
> How to define f?
>
>
> Skip
>
>
>
>
>
> On Wed, Jan 15, 2020 at 8:30 PM Skip Cave
> wrote:
>
> > How does one apply a monadic verb repetitively to every nth element of
> > a one1-dimentional array?
> >
> > For example:
> >
> >]a=.i.20
> > 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
> > n=.3
> >
> > NB. Design u to increment every nth integer in a:
> >
> >
> > u=.??: > n u a
> > 1 1 2 4 4 5 7 7 8 10 10 11 13 13 14 16 16 17 19 19
> >
> --
> For information about J forums see http://www.jsoftware.com/forums.htm
--
For information about J forums see http://www.jsoftware.com/forums.htm
Re: [Jprogramming] Selective verb application
I'm thinking of something along the lines of # (copy) 1 1 1 0 1 0 0 1 0 1 # i.10 0 1 2 4 7 9 Only "apply" uses a boolean left argument to define which elements on the right are affected by the verb: 1 1 1 0 1 0 0 1 0 1 (apply -.) 1 1 1 1 1 1 1 1 1 1 0 0 0 1 0 1 1 0 1 0 1 1 1 0 1 0 0 1 0 1 (apply 2&+) 1 1 1 1 1 1 1 1 1 1 3 3 3 1 3 1 1 3 1 3 1 1 1 0 1 0 0 1 0 1 (apply 2&^~) i.10 0 1 4 3 16 5 6 49 8 81 Is this possible? Skip Cave Cave Consulting LLC On Thu, Jan 16, 2020 at 2:08 AM Arnab Chakraborty wrote: > My first idea was to use ^: . But I am unable to get a solution. None of > the posted solutions use ^: either. Just wondering whether ^: can help > here. > > On Thu, 16 Jan 2020, 12:36 'robert therriault' via Programming, < > programm...@jsoftware.com> wrote: > > > It is too late, considering the result is not the one that you requested! > > > > Anyway I would use a numerical approach something like the incorrect one > > that I just posted. > > > > Sheepishly - Cheers, bob > > > > > On Jan 15, 2020, at 23:03, 'robert therriault' via Programming < > > programm...@jsoftware.com> wrote: > > > > > > Hi Skip, > > > > > > A late snowy night silly approach > > > > > >]a=.20#1 > > > 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 > > > f1=. *@(3&|)@:i.@:# NB. mod 3 non-zeros > > > f1 a > > > 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 > > > f2=. -.@*@(2&|)@:i.@:# NB. mod 2 zeros > > > f2 a > > > 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 > > > (f1 *: f2) a NB. Not-And fork > > > 1 1 0 1 0 1 1 1 0 1 0 1 1 1 0 1 0 1 1 1 > > > f=. f1 *: f2 NB. requested result > > > f a > > > 1 1 0 1 0 1 1 1 0 1 0 1 1 1 0 1 0 1 1 1 > > > > > > Cheers, bob > > > > > > > > >> On Jan 15, 2020, at 22:29, Skip Cave wrote: > > >> > > >> ]a=.20#1 > > > > > > -- > > > 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
Re: [Jprogramming] Selective verb application
My first idea was to use ^: . But I am unable to get a solution. None of the posted solutions use ^: either. Just wondering whether ^: can help here. On Thu, 16 Jan 2020, 12:36 'robert therriault' via Programming, < programm...@jsoftware.com> wrote: > It is too late, considering the result is not the one that you requested! > > Anyway I would use a numerical approach something like the incorrect one > that I just posted. > > Sheepishly - Cheers, bob > > > On Jan 15, 2020, at 23:03, 'robert therriault' via Programming < > programm...@jsoftware.com> wrote: > > > > Hi Skip, > > > > A late snowy night silly approach > > > >]a=.20#1 > > 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 > > f1=. *@(3&|)@:i.@:# NB. mod 3 non-zeros > > f1 a > > 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 > > f2=. -.@*@(2&|)@:i.@:# NB. mod 2 zeros > > f2 a > > 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 > > (f1 *: f2) a NB. Not-And fork > > 1 1 0 1 0 1 1 1 0 1 0 1 1 1 0 1 0 1 1 1 > > f=. f1 *: f2 NB. requested result > > f a > > 1 1 0 1 0 1 1 1 0 1 0 1 1 1 0 1 0 1 1 1 > > > > Cheers, bob > > > > > >> On Jan 15, 2020, at 22:29, Skip Cave wrote: > >> > >> ]a=.20#1 > > > > -- > > 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
Re: [Jprogramming] Selective verb application
It is too late, considering the result is not the one that you requested! Anyway I would use a numerical approach something like the incorrect one that I just posted. Sheepishly - Cheers, bob > On Jan 15, 2020, at 23:03, 'robert therriault' via Programming > wrote: > > Hi Skip, > > A late snowy night silly approach > >]a=.20#1 > 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 > f1=. *@(3&|)@:i.@:# NB. mod 3 non-zeros > f1 a > 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 > f2=. -.@*@(2&|)@:i.@:# NB. mod 2 zeros > f2 a > 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 > (f1 *: f2) a NB. Not-And fork > 1 1 0 1 0 1 1 1 0 1 0 1 1 1 0 1 0 1 1 1 > f=. f1 *: f2 NB. requested result > f a > 1 1 0 1 0 1 1 1 0 1 0 1 1 1 0 1 0 1 1 1 > > Cheers, bob > > >> On Jan 15, 2020, at 22:29, Skip Cave wrote: >> >> ]a=.20#1 > > -- > For information about J forums see http://www.jsoftware.com/forums.htm -- For information about J forums see http://www.jsoftware.com/forums.htm
Re: [Jprogramming] Selective verb application
Hi Skip, A late snowy night silly approach ]a=.20#1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 f1=. *@(3&|)@:i.@:# NB. mod 3 non-zeros f1 a 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 f2=. -.@*@(2&|)@:i.@:# NB. mod 2 zeros f2 a 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 (f1 *: f2) a NB. Not-And fork 1 1 0 1 0 1 1 1 0 1 0 1 1 1 0 1 0 1 1 1 f=. f1 *: f2 NB. requested result f a 1 1 0 1 0 1 1 1 0 1 0 1 1 1 0 1 0 1 1 1 Cheers, bob > On Jan 15, 2020, at 22:29, Skip Cave wrote: > > ]a=.20#1 -- For information about J forums see http://www.jsoftware.com/forums.htm
Re: [Jprogramming] Selective verb application
Suppose I want to invert every 3rd binary bit, then every second bit where f is -. (selective not): ]a=.20#1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ]b=.3 f a 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 ]c .2 f b 1 1 0 0 0 1 1 1 0 0 0 1 1 1 0 0 0 1 1 1 How to define f? Skip On Wed, Jan 15, 2020 at 8:30 PM Skip Cave wrote: > How does one apply a monadic verb repetitively to every nth element of a > one1-dimentional array? > > For example: > >]a=.i.20 > 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 > n=.3 > > NB. Design u to increment every nth integer in a: > > > u=.??: n u a > 1 1 2 4 4 5 7 7 8 10 10 11 13 13 14 16 16 17 19 19 > -- For information about J forums see http://www.jsoftware.com/forums.htm
Re: [Jprogramming] Selective verb application
(flashing I-am-bad-at-J disclaimer)
Consider:
]a=.i.20
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
_3[\ a
0 1 2
3 4 5
6 7 8
9 10 11
12 13 14
15 16 17
18 19 0
every third element's right there in the first column.
thus:
th =: 1 : ',(u@:{."1 ,. }."1) (-x)[\y'
which reshapes the list, applies the verb to the first column, then
stitches the result of that to the other columns, then returns a list.
3 (_"_) th a
_ 1 2 _ 4 5 _ 7 8 _ 10 11 _ 13 14 _ 16 17 _ 19 0
4 (_"_) th a
_ 1 2 3 _ 5 6 7 _ 9 10 11 _ 13 14 15 _ 17 18 19
5 (_"_) th a
_ 1 2 3 4 _ 6 7 8 9 _ 11 12 13 14 _ 16 17 18 19
The resulting list can be padded with zeroes, but since the passed verb
will never apply to those, you can just strip them back off:
th =: 1 : '(#y) $ ,(u@:{."1 ,. }."1) (-x)[\y'
19 (_"_) th a
_ 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 _
NB. ^^^not still padded with 18 zeroes
On Wed, 2020-01-15 at 20:30 -0600, Skip Cave wrote:
> How does one apply a monadic verb repetitively to every nth element
> of a
> one1-dimentional array?
>
> For example:
>
>]a=.i.20
> 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
> n=.3
>
> NB. Design u to increment every nth integer in a:
>
>
> u=.??: n u a
> 1 1 2 4 4 5 7 7 8 10 10 11 13 13 14 16 16 17 19 19
> ---
> ---
> For information about J forums see
> http://www.jsoftware.com/forums.htm
--
For information about J forums see http://www.jsoftware.com/forums.htm
Re: [Jprogramming] Selective verb application
This works too : ,1 >:`+`+\i.20 1 1 2 4 4 5 7 7 8 10 10 11 13 13 14 16 16 17 19 19 On Wed, Jan 15, 2020 at 9:37 PM Roger Hui wrote: > Depends on the verb. In the case >:, > >a=: i. 20 >n=: 3 >a + 0=n|i.#a > 1 1 2 4 4 5 7 7 8 10 10 11 13 13 14 16 16 17 19 19 > > Basically apply the verb or the identity function, depending on 0=n|i.#a . > > > > On Wed, Jan 15, 2020 at 6:30 PM Skip Cave wrote: > > > How does one apply a monadic verb repetitively to every nth element of a > > one1-dimentional array? > > > > For example: > > > >]a=.i.20 > > 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 > > n=.3 > > > > NB. Design u to increment every nth integer in a: > > > > > > u=.??: > n u a > > 1 1 2 4 4 5 7 7 8 10 10 11 13 13 14 16 16 17 19 19 > > -- > > 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
Re: [Jprogramming] Selective verb application
Depends on the verb. In the case >:, a=: i. 20 n=: 3 a + 0=n|i.#a 1 1 2 4 4 5 7 7 8 10 10 11 13 13 14 16 16 17 19 19 Basically apply the verb or the identity function, depending on 0=n|i.#a . On Wed, Jan 15, 2020 at 6:30 PM Skip Cave wrote: > How does one apply a monadic verb repetitively to every nth element of a > one1-dimentional array? > > For example: > >]a=.i.20 > 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 > n=.3 > > NB. Design u to increment every nth integer in a: > > > u=.??: n u a > 1 1 2 4 4 5 7 7 8 10 10 11 13 13 14 16 16 17 19 19 > -- > For information about J forums see http://www.jsoftware.com/forums.htm > -- For information about J forums see http://www.jsoftware.com/forums.htm
