[R] how to calculate means of matrix elements

Gabor Grothendieck ggrothendieck at gmail.com
Tue May 19 05:21:53 CEST 2009


Try this:

(mat1 + mat2 + mat3) / 3

On Mon, May 18, 2009 at 8:40 PM, dxc13 <dxc13 at health.state.ny.us> wrote:
>
> useR's,
> I have several matrices of size 4x4 that I want to calculate means of their
> respective positions with.  For example, consider I have 3 matrices given by
> the code:
> mat1 <- matrix(sample(1:20,16,replace=T),4,4)
> mat2 <- matrix(sample(-5:15,16,replace=T),4,4)
> mat3 <- matrix(sample(5:25,16,replace=T),4,4)
>
> The result I want is one matrix of size 4x4 in which position [1,1] is the
> mean of position [1,1] of the given three matrices.  The same goes for all
> other positions of the matrix.  If these three matrices are given in
> separate text files, how can I write code that will get this result I need?
>
> Thanks in advance,
> dxc13
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