[R] matrix position to list of coordinates

[Sarah Goslee]

Here's one way:
> data.frame(rowID=as.vector(row(A)), colID=as.vector(col(A)), A=as.vector(A))
  rowID colID A
1     1     1 1
2     2     1 2
3     1     2 3
4     2     2 4
5     1     3 5
6     2     3 6
7     1     4 7
8     2     4 8

You can sort that as desired.

Sarah

On Sun, Jan 1, 2012 at 5:21 PM, Ana <rrasterr at gmail.com> wrote:
> How can I extract a list of the positions in the matrix?
>> A=matrix(1:8, nrow=2,ncol=4)
>> A
>     [,1] [,2] [,3] [,4]
> [1,]    1    3    5    7
> [2,]    2    4    6    8
>
>
> Something like this
>
> pos.A
>
> 1 1
> 1 2
> 1 3
> 1 4
> 2 1
> 2 2
> 2 3
> 2 4
>

-- 
Sarah Goslee
http://www.functionaldiversity.org