Well, at first I did not realize that
c (({. ; }.)@":@,) d
evaluates as
({. ; }.)":(c,d)
, but after that everything was clear.
You were right, it was fun.
Ben
________________________________________
From: [email protected]
[[email protected]] on behalf of Raul Miller
[[email protected]]
Sent: Saturday, November 02, 2013 13:07
To: Programming forum
Subject: Re: [Jprogramming] Times Table Therapy
Do you want an explanation? Or would it be more fun to work it out by
yourself?
Thanks,
--
Raul
On Sat, Nov 2, 2013 at 7:37 AM, Ben Gorte - CITG <[email protected]>wrote:
> Do you mean the over/by thing of
> http://www.jsoftware.com/help/dictionary/intro03.htm ?
>
> over =: ({. ; }.)@":@,
> by =: ' '&;@,.@[ ,. ]
> b by (c over d)
> ┌──┬─────────────────────────────┐
> │ │ 4 3 2 1 0 _1 _2 _3 _4│
> ├──┼─────────────────────────────┤
> │_4│_16 _12 _8 _4 0 4 8 12 16│
> │_3│_12 _9 _6 _3 0 3 6 9 12│
> │_2│ _8 _6 _4 _2 0 2 4 6 8│
> │_1│ _4 _3 _2 _1 0 1 2 3 4│
> │ 0│ 0 0 0 0 0 0 0 0 0│
> │ 1│ 4 3 2 1 0 _1 _2 _3 _4│
> │ 2│ 8 6 4 2 0 _2 _4 _6 _8│
> │ 3│ 12 9 6 3 0 _3 _6 _9 _12│
> │ 4│ 16 12 8 4 0 _4 _8 _12 _16│
> └──┴─────────────────────────────┘
>
> (not that I competely understand it, by the way).
>
> Ben
> ________________________________________
> From: [email protected] [
> [email protected]] on behalf of Linda Alvord [
> [email protected]]
> Sent: Saturday, November 02, 2013 11:27
> To: [email protected]
> Subject: [Jprogramming] Times Table Therapy
>
> Maybe these will be better boxes.
>
> a=:' '
> b=:i:4
> c=:i:_4
> d=:b*/c
>
> b,d
> _4 _3 _2 _1 0 1 2 3 4
> _16 _12 _8 _4 0 4 8 12 16
> _12 _9 _6 _3 0 3 6 9 12
> _8 _6 _4 _2 0 2 4 6 8
> _4 _3 _2 _1 0 1 2 3 4
> 0 0 0 0 0 0 0 0 0
> 4 3 2 1 0 _1 _2 _3 _4
> 8 6 4 2 0 _2 _4 _6 _8
> 12 9 6 3 0 _3 _6 _9 _12
> 16 12 8 4 0 _4 _8 _12 _16
>
> ]e=:(<b),:<d
> ------------------------------┐
> │_4 _3 _2 _1 0 1 2 3 4 │
> +-----------------------------+
> │_16 _12 _8 _4 0 4 8 12 16│
> │_12 _9 _6 _3 0 3 6 9 12│
> │ _8 _6 _4 _2 0 2 4 6 8│
> │ _4 _3 _2 _1 0 1 2 3 4│
> │ 0 0 0 0 0 0 0 0 0│
> │ 4 3 2 1 0 _1 _2 _3 _4│
> │ 8 6 4 2 0 _2 _4 _6 _8│
> │ 12 9 6 3 0 _3 _6 _9 _12│
> │ 16 12 8 4 0 _4 _8 _12 _16│
> L------------------------------
>
> ]f=:(<a),:<,.c
> ---┐
> │ │
> +--+
> │ 4│
> │ 3│
> │ 2│
> │ 1│
> │ 0│
> │_1│
> │_2│
> │_3│
> │_4│
> L---
>
> f,.e
> ---T-----------------------------┐
> │ │_4 _3 _2 _1 0 1 2 3 4 │
> +--+-----------------------------+
> │ 4│_16 _12 _8 _4 0 4 8 12 16│
> │ 3│_12 _9 _6 _3 0 3 6 9 12│
> │ 2│ _8 _6 _4 _2 0 2 4 6 8│
> │ 1│ _4 _3 _2 _1 0 1 2 3 4│
> │ 0│ 0 0 0 0 0 0 0 0 0│
> │_1│ 4 3 2 1 0 _1 _2 _3 _4│
> │_2│ 8 6 4 2 0 _2 _4 _6 _8│
> │_3│ 12 9 6 3 0 _3 _6 _9 _12│
> │_4│ 16 12 8 4 0 _4 _8 _12 _16│
> L--+------------------------------
>
>
>
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