Here's a definition for at which works exactly like @

   at=: 2 :'([: u v)"v

For example:'
   <at i. at > 2 3 4

Now, looking at that, you may think that this means that [: is somehow
superior to @ but note that [: is not necessary

   at=: 2 :'u@:v"v'

Note that in J, @: and @ (without the colon) are different words.

It's also possible to replace @: with an explicit definition, but
that's probably best left for another time.

FYI,

-- 
Raul

On Wed, Jan 2, 2013 at 3:02 AM, Linda Alvord <[email protected]> wrote:
> Here’s another, hopefully simpler, example of my problem with   @
>
>     ]a=:?>:i.6
>
> 0 1 1 3 1 5
>
>    ]a=:=a
>
> 1 0 0 0 0 0
>
> 0 1 1 0 1 0
>
> 0 0 0 1 0 0
>
> 0 0 0 0 0 1
>
>    ]b=:?>:i.6
>
> 0 1 0 3 1 3
>
>    a #@# b
>
> 1 3 1 1
>
>
>
> There must be some way to get this result without  @
>
>
>
> Here are some of the things I have tried:
>
>
>
> NB.  x u@v y ↔ u x v y  (vocabulary definition of  @
>
>    #a#b
>
> 4
>
>
>
> NB.  ([: f g)"({. g b. 0) <=> f@g  (someone on the forum provided this in
> an earlier struggle I had with  @ )
>
>      a(([:##)"({.# b. 0))b
>
> 4
>
>
>
> Both of these definitions appear to describe  @:
>
>    a #@:# b
>
> 4
>
>
>
> Are changes ever made to the definitions in the vocabulary when they are
> unclear or incorrect?
>
>
>
> Linda
>
> ----------------------------------------------------------------------
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