[R] sum

[Deepayan Sarkar]

On Wednesday 23 April 2003 12:57 pm, Luis Silva wrote:
> Dear helpers
>
> I have a list where each element is a matrix (the list is
> obtained with lapply). I want to sum those matrices. Is there a
> function to do that? The sum function sums all the elements...

If the list is not too long, perhaps

sumlist <- 
    function(x) 
        if (length(x) > 2) sumlist(x[1:2]) + 
             sumlist(x[-(1:2)]) else do.call("+", x) 



sumlist(<whatever your list is>)


-Deepayan