aperm

aperm(a, perm)
Permute the dimensions of an array.
  • a – An array.
  • perm – A permutation of the numbers 1:k, where k is the number of dimensions in array a. The default permutation is k:1.

Example. A simple array a is initialized with values 1 through 12. Array b is a permutation of a where the second dimension of a is the first dimension of b, and so on. Finally, we verify the permutation worked as expected.
> a    <- array(1:(2*2*3), c(2,2,3))
> perm <- c(2,3,1)
> b    <- aperm(a, perm)
> 
> a[1,2,3]
[1] 11
> c(1,2,3)[perm]
[1] 2 3 1
> b[2,3,1]
[1] 11
> 
> a[2,2,1]
[1] 4
> c(2,2,1)[perm]
[1] 2 1 2
> b[2,1,2]
[1] 4

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