(id {~ ])?
I don't understand the usage of ] in the above.
From the NuVoc docs:
Use in the J session to both display a noun and assign it to a name with a
single sentence
] z=: i:2
_2 _1 0 1 2
Typo?
(id {~ ]) move?
What does it expand to? Where's the assignment of a function to a name?
Earlier, I tried to curry the { function
move { id
to
f =: (id & {~)
Seemed like that should work, like this
f 0 2 5 => 3 by 15 array
but I think I got a syntax error when I tried it.
I couldn't get get J running on my Fedora 24 install (where I am now), so
put it on Win 10 on my dual-boot box and will get back to it after I run
some errands.
Thanks, all.
On Mon, May 29, 2017 at 10:27 AM, Raul Miller <[email protected]> wrote:
> Hmm...
>
> First, here's an expression for a 15 by 15 identity matrix:
>
> id=: 15 15$16{.1
>
> But (id {~) is invalid syntax, so perhaps, instead use =&(i.15)"0
>
> For example:
>
> =&(i.15)"0 ] 2 3 5
> 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0
> 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0
> 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0
>
> That said, (id {~ ]) is syntactically valid and does the same thing
> (except for arguments outside the domain).
>
> I hope this helps,
>
> --
> Raul
>
>
> On Mon, May 29, 2017 at 9:22 AM, Michael Rice <[email protected]> wrote:
> > Thanks.
> >
> > I found that after I couldn't find it and wrote my own, but it seemed to
> be
> > changing one of my function parameters, the left one, so I moved back to
> my
> > definition.
> >
> > I'm again having a similar problem stringing these verbs, adverbs, etc.
> > together to form the function I want.
> >
> > I created an 15 by 15 identity matrix, call it id, and substituted this
> >
> > (1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 |.!.0~
> > 3 1 $ -)
> >
> > for this
> >
> > (id {~)
> >
> > Much cleaner and, no doubt, faster. Win. Win.
> >
> > Naively, I thought this simple substitution of the two would work
> >
> > make_move =: ((+. *. -.@:*.) +./) (id {~)
> >
> > Nope. Syntax error.
> >
> > Have already tried several other variations this AM with the same result.
> >
> > I'm using "Learning J" as a reference and NuVoc.
> >
> > http://www.jsoftware.com/help/learning/contents.htm
> >
> >
> >
> >
> >
> >
> >
> > On Sun, May 28, 2017 at 9:57 PM, David Lambert <[email protected]>
> wrote:
> >
> >> xor can be not equal ~:
> >>
> >> or bitwise 2b10110 b.
> >>
> >>
> >>
> >> On 05/28/2017 08:00 AM, [email protected] wrote:
> >>
> >>> Message: 5
> >>> Date: Sat, 27 May 2017 23:51:29 -0400
> >>> From: Michael Rice<[email protected]>
> >>> To: programming<[email protected]>
> >>> Subject: Re: [Jprogramming] Function creation, without creating
> >>> subfunctions
> >>> Message-ID:
> >>> <CAGw08vM_5CttMFY45F6zAAto-doycQYkXqRf8uRWC=0Ug9xcOw@mail.
> >>> gmail.com>
> >>> Content-Type: text/plain; charset="UTF-8"
> >>>
> >>> Yes, that worked. New board created, without changing the old board or
> the
> >>> move.
> >>>
> >>> board =: 1 1 1 1 1 0 1 1 1 1 1 1 1 1 1
> >>> move =: 0 2 5
> >>> make_move =: ((+. *. -.@:*.) +./) (1 0 0 0 0 0 0 0 0 0 0 0 0 0 0
> >>> |.!.0~
> >>> 3 1 $ -)
> >>> board make_move move
> >>> 0 1 0 1 1 1 1 1 1 1 1 1 1 1 1
> >>> board
> >>> 1 1 1 1 1 0 1 1 1 1 1 1 1 1 1
> >>> move
> >>> 0 2 5
> >>>
> >>
> >> ----------------------------------------------------------------------
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> > ----------------------------------------------------------------------
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> ----------------------------------------------------------------------
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