Create a matrix from a vector in R

Question

I have a vector v , and I would like to create the following matrix. How can I do this in R?

      v = c(1, 2, 3, 4)

      > m = matrix(c(1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4,4), nrow=4)
      > m
           [,1] [,2] [,3] [,4]
     [1,]    1    2    3    4
     [2,]    1    2    3    4
     [3,]    1    2    3    4
     [4,]    1    2    3    4

Answer 1

See ?matrix and the nrow , ncol , byrow arguments:

matrix(v, nrow=4, ncol=4, byrow=TRUE)
#     [,1] [,2] [,3] [,4]
#[1,]    1    2    3    4
#[2,]    1    2    3    4
#[3,]    1    2    3    4
#[4,]    1    2    3    4