[R] How to sum a list of matrices ?

Alain Guillet alain.guillet at uclouvain.be
Wed Mar 10 16:54:29 CET 2010


Hi,

Look at the R News 8/1 in the R Help Desk.

Alain

On 10-Mar-10 16:34, Carlos Petti wrote:
> Dear list,
>
> I have a list of three matrices :
>
> i = list(matrix(1:4,2,2), matrix(3:6,2,2), matrix(9:12,2,2))
>
> I would like to sum the matrices, as follows :
>
> [,1] [,2]
> [1,] 13 19
> [2,] 16 22
>
> I used this code :
>
> k<- i[[1]]
> for (j in (2:length(i))) {
> k<- k + i[[j]]}
>
> But, is it possible to sum without a loop ?
>
> Thanks in advance,
> Carlos
>
> 	[[alternative HTML version deleted]]
>
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>    

-- 
Alain Guillet
Statistician and Computer Scientist

SMCS - IMMAQ - Université catholique de Louvain
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