Providing a reproducible example is a good idea, but what about this:
> A <- matrix(1:20, nrow=4)
> MASK <- matrix(FALSE, nrow=4, ncol=5)
> MASK[2:3, 1:3] <- TRUE
> MASK
[,1] [,2] [,3] [,4] [,5]
[1,] FALSE FALSE FALSE FALSE FALSE
[2,] TRUE TRUE TRUE FALSE FALSE
[3,] TRUE TRUE TRUE FALSE FALSE
[4,] FALSE FALSE FALSE FALSE FALSE
> A[rowSums(MASK) > 0, colSums(MASK) > 0]
[,1] [,2] [,3]
[1,] 2 6 10
[2,] 3 7 11
Alternatively, you could take the vector returned by:
> A[MASK]
[1] 2 3 6 7 10 11
and put it back into matrix format.
Sarah
On Tue, Jun 12, 2012 at 12:44 PM, Michael <comtech....@gmail.com> wrote:
> Hi all,
>
> Lets say I have a matrix A which is m x n.
>
> I also have a mask matrix MASK which is m x n with values in T/F, where T
> values make a sub-matrix in regutangular shape...
>
> I applied B=A[MASK] and it didn't work as expected...
>
> Any thoughts?
--
Sarah Goslee
http://www.functionaldiversity.org
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