Re: [R] Summing up matrices in a list

From: Marc Schwartz <MSchwartz_at_medanalytics.com>
Date: Thu 17 Mar 2005 - 03:30:15 EST

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



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