Rotate a Matrix in R

Question

I have a matrix in R like this:

|1|2|3|
|1|2|3|
|1|2|3|

Is there an easy way to rotate the entire matrix by 90 degrees clockwise to get the

Answer 1

m <- matrix(rep(1:3,each=3),3)

     [,1] [,2] [,3]
[1,]    1    2    3
[2,]    1    2    3
[3,]    1    2    3

t(m[nrow(m):1,])

     [,1] [,2] [,3]
[1,]    1    1    1
[2,]    2    2    2
[3,]    3    3    3

m[nrow(m):1,ncol(m):1]

     [,1] [,2] [,3]
[1,]    3    2    1
[2,]    3    2    1
[3,]    3    2    1

t(m)[ncol(m):1,]

     [,1] [,2] [,3]
[1,]    3    3    3
[2,]    2    2    2
[3,]    1    1    1