[R] Summing up matrices in a list

[Marc Schwartz]

On Wed, 2005-03-16 at 18:21 +0200, Vicky Landsman wrote:
> Dear all,
> I think that my question is very simple but I failed to solve it. 
> I have a list which elements are matrices like this:
>  
> >mylist  
> [[1]]
>      [,1] [,2] [,3]
> [1,]    1    3    5
> [2,]    2    4    6
> 
> [[2]]
>      [,1] [,2] [,3]
> [1,]    7    9   11
> [2,]    8   10   12
> 
> I'd like to create a matrix M<-mylist[[1]]+mylist[[2]]
>      [,1] [,2] [,3]
> [1,]    8   12   16
> [2,]   10   14   18
> 
> Is there a way to create M without looping? 
> Thanks a lot, 


> do.call("+", mylist)
     [,1] [,2] [,3]
[1,]    8   12   16
[2,]   10   14   18

See ?do.call for more information.

HTH,

Marc Schwartz