Convert column vector to the diagonal of a matrix in R?

Question

I have an column vector with following format in R: num [1:2464, 1].

I want to diagonal the vector, so each element is in the diagonal of the matrix. I have tried the following code:

diagvector <- diag(myvector)

But then it just show the first number. I think I only can use that code if my vector have the following form: num [1:2464].

So how do I a) change the format from num [1:2464, 1] to num [1:2464] for my vector, or b) take the diagonal to my vector with the format num [1:2464, 1]?

Answer 1

Your "column vector" is actually a matrix as it has two dimensions, but it can be formed into a vector.

myvector <- matrix(1:2464, 1)
diagvector <- diag(c(myvector))
diagvector

        [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12] [,13]    ...
   [1,]    1    0    0    0    0    0    0    0    0     0     0     0     0
   [2,]    0    2    0    0    0    0    0    0    0     0     0     0     0
   [3,]    0    0    3    0    0    0    0    0    0     0     0     0     0
   [4,]    0    0    0    4    0    0    0    0    0     0     0     0     0
   [5,]    0    0    0    0    5    0    0    0    0     0     0     0     0
   [6,]    0    0    0    0    0    6    0    0    0     0     0     0     0
   [7,]    0    0    0    0    0    0    7    0    0     0     0     0     0
   [8,]    0    0    0    0    0    0    0    8    0     0     0     0     0
   [9,]    0    0    0    0    0    0    0    0    9     0     0     0     0
  [10,]    0    0    0    0    0    0    0    0    0    10     0     0     0
  [11,]    0    0    0    0    0    0    0    0    0     0    11     0     0
  [12,]    0    0    0    0    0    0    0    0    0     0     0    12     0
  [13,]    0    0    0    0    0    0    0    0    0     0     0     0    13
    ...

Or:

myvector <- matrix(1:2464, 1)
diagvector <- diag(length(myvector)) * c(myvector)
diagvector