Adding corresponding elements in a list in R

Question

I have a list that contains multiple matrices (from 2 to n). For simplicity's sake, let's say I have a list of 5 matrices as follows.

> lst
[[1]]
     [,1] [,2] [,3] [,4] [,5]
[1,]    1    1    1    1    1
[2,]    1    1    1    1    1

[[2]]
     [,1] [,2] [,3] [,4] [,5]
[1,]    2    2    2    2    2
[2,]    2    2    2    2    2
...
[[5]]
     [,1] [,2] [,3] [,4] [,5]
[1,]    5    5    5    5    5
[2,]    5    5    5    5    5

How do I perform an operation (something like colSums but for lists) to add these together and get a single matrix as the output:

     [,1] [,2] [,3] [,4] [,5]
[1,]   15   15   15   15   15
[2,]   15   15   15   15   15

I tried mapply(sum,lst[[1]],lst[[2]],lst[[3]],lst[[4]],lst[[5]]). This does get me the sum, but the matrix loses its shape and requires naming each list item (maybe okay with 5, but what if I have 100?).

Answer 1

This should do it

Reduce('+', lst)