Here are some perhaps relevant examples:
1 1 0 1 #inv (3 3$ 0)
0 0 0
0 0 0
0 0 0
0 0 0
1 1 0 1 #inv!.1 (3 3$ 0)
0 0 0
0 0 0
1 1 1
0 0 0
1 1 0 1 #inv!.1"1 (3 3$ 0)
0 0 1 0
0 0 1 0
0 0 1 0
1 1 0 1 #inv!.1"1 (1 1 0 1) #inv!.1 (3 3$ 0)
0 0 1 0
0 0 1 0
1 1 1 1
0 0 1 0
1 1 0 1 # 1 1 0 1 #inv!.1"1 (1 1 0 1) #inv!.1 (3 3$ 0)
0 0 1 0
0 0 1 0
0 0 1 0
1 1 0 1 #("1) 1 1 0 1 # 1 1 0 1 #inv!.1"1 (1 1 0 1) #inv!.1 (3 3$ 0)
0 0 0
0 0 0
0 0 0
(i.3) 2} 1 1 0 1 #inv (3 3$0)
0 0 0
0 0 0
0 1 2
0 0 0
(i.4) 2}"0 1 (1 1 0 1) #inv"1 (i.3) 2} 1 1 0 1 #inv (3 3$0)
0 0 0 0
0 0 1 0
0 1 2 2
0 0 3 0
(i.4) 2}"0 1 (1 1 0 1) #inv"1 (0 1 3) 2} 1 1 0 1 #inv (3 3$0)
0 0 0 0
0 0 1 0
0 1 2 3
0 0 3 0
The whole #inv thing is a bit quirky but was quite deliberate. This was a
primitive in APL, but the syntax was ... strange. Rather than trying to
find a special symbol for this operation, Iverson put it on #inv (since -
logically speaking - it's the inverse of #).
Thanks,
--
Raul
On Thu, Sep 11, 2014 at 5:21 AM, Sebastian <[email protected]> wrote:
> Hi,
>
> I know the verbs , ,. ,: to add rows, columns and dimensions to matrices.
> It is easy to add these to begin or the end of the corrosponding dimension,
> but what is to do, if I want to add one row/column in the middle of a
> matrix? Is the only way to slice the matrix in two pieces and join them
> with the new row/column?
>
> A few examples:
>
> Initial situation:
>
> 3 3 $ 0
> 0 0 0
>
> 0 0 0
>
> 0 0 0
>
>
> add column somewhere to the middle:
>
> 0 0 1 0
>
> 0 0 1 0
>
> 0 0 1 0
>
>
>
> add row somewhere to the middle:
>
> 0 0 1 0
>
> 0 0 1 0
>
> 1 1 1 1
>
> 0 0 1 0
>
>
> remove the added column:
>
> 0 0 0
>
> 0 0 0
>
> 1 1 1
>
> 0 0 0
>
>
>
> and the row:
>
>
>
> 0 0 0
>
> 0 0 0
>
> 0 0 0
>
>
>
> Can anyone help me with this?
>
>
>
> Regards
>
> Sebastian
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