Raul said:

However, (1 2 3) is not a verb. So that gives you a domain error right
there, regardless of any right argument:

Doh! NOW i get it. ] is the verb and 3 is the noun.

So any verb should work...

3<\1 2 3 4 5

┌─────┬─────┬─────┐

│ 1 2 3 │ 2 3 4 │ 3 4 5 │

└─────┴─────┴─────┘


3{.\1 2 3 4 5

1 2 3

Hmmm..  why didn't that last one work?  Wait! I think I know...

3{."1\1 2 3 4 5

1 2 3

Nope,

3{."0\1 2 3 4 5

1 2 3

2 3 4

3 4 5

Yes! I'm not exactly sure why, but that's another way to achieve the same
result that I was originally trying for.

Skip






Skip Cave
Cave Consulting LLC

On Mon, Feb 19, 2018 at 1:47 PM, Raul Miller <rauldmil...@gmail.com> wrote:

> [I'm using parenthesis, here to separate j expressions from
> surrounding english text. That might be a little unfamiliar, but
> hopefully it's not too bad... And, on the plus side, parenthesis are
> valid J when their contents are valid J.]
>
> ] does replicate the right argument. And, for monadic verbs - which is
> what we get for (x verb\ y) contexts - the right argument is the only
> argument.
>
> But keep in mind that the verb (]\) has two definitions: a monadic
> definition and a dyadic definition. So you should expect a different
> result from (3 ]\ i.4) than what you get from (]\ i.4)
>
> And, this might be throwing you off: both (x verb\ y) and (verb\ y)
> use the monadic definition of (\)'s verb argument.
>
> However, (1 2 3) is not a verb. So that gives you a domain error right
> there, regardless of any right argument:
>
>    1 2 3\
> |domain error
>
> To see what ] is doing, though, maybe it's better to replace it with <
>
> For example, try:   3 <\ i.6
>
> Thanks,
>
> --
> Raul
>
>
>
> On Mon, Feb 19, 2018 at 2:38 PM, Skip Cave <s...@caveconsulting.com>
> wrote:
> > Thanks to all the informative responses. I knew there had to be a way to
> > use \ for the sliding window, but
> > it didn't occur to me to use ] to access the right argument.
> >
> > so
> >
> > ]\1 2 3
> >
> > 1 0 0
> >
> > 1 2 0
> >
> > 1 2 3
> >
> > but
> >
> > 1 2 3\1 2 3
> >
> > |domain error
> >
> > | 1 2 3 \1 2 3
> >
> > I thought that  ] replicated the right argument, but appaently not.
> >
> > Why does the first example work, and the second doesn't?
> > What exactly is the ] doing in the first example?
> >
> > Skip
> >
> >
> > Skip Cave
> > Cave Consulting LLC
> >
> > On Mon, Feb 19, 2018 at 1:09 PM, Skip Cave <s...@caveconsulting.com>
> wrote:
> >
> >> How can one create a sliding window in J?
> >>
> >> 3 sw i.6
> >>
> >> 0 1 2
> >> 1 2 3
> >> 2 3 4
> >> 3 4 5
> >>
> >> 4 sw i.7
> >> 0 1 2 3
> >> 1 2 3 4
> >> 2 3 4 5
> >> 3 4 5 6
> >> 4 5 6 7
> >>
> >> What is the J code for sw?
> >>
> >>
> >>
> >>
> >>
> >> Skip Cave
> >> Cave Consulting LLC
> >>
> > ----------------------------------------------------------------------
> > For information about J forums see http://www.jsoftware.com/forums.htm
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
>
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