从矩阵列表中提取矩阵

Question

Say I have a list of 3 Matrices. How do I extract one of the matrices as a Matrix-Object, so I can further access it's elements with mymatrix[i,j] calls?

mylist[i] simply returns a List-Object with Matrix i .

I'm sure there has to be a simple solution, but I couldn't manage to find one.

Answer 1

use double brackets: mylist[[i]] ....

From ?"[[" (emphasis added):

Recursive (list-like) objects:

Indexing by '[' is similar to atomic vectors and selects a list of the specified element(s) .

Both '[[' and '$' select a single element of the list . The main difference is that '$' does not allow computed indices,

Answer 2

mylist[[1]] should return you the first matrix

mylist[[3]] should return you the third matrix

Answer 3

If you want to automate this you could simply run:

for (index in 1:length(mylist)){
    assign(paste0("matrix", index), mylist[[index]], envir = .GlobalEnv)
}