aperm {base}

R Documentation

Array Transposition

Description

Transpose an array by permuting its dimensions and optionally resizing it.

Usage

aperm(a, perm, resize = TRUE)

Arguments

a	the array to be transposed.
perm	the subscript permutation vector, which must be a permutation of the integers 1:n, where n is the number of dimensions of a. The default is to reverse the order of the dimensions.
resize	a flag indicating whether the vector should be resized as well as having its elements reordered (default TRUE).

Value

A transposed version of array a, with subscripts permuted as indicated by the array perm. If resize is TRUE, the array is reshaped as well as having its elements permuted, the dimnames are also permuted; if resize = FALSE then the returned object has the same dimensions as a, and the dimnames are dropped. In each case other attributes are copied from a.

The function t provides a faster and more convenient way of transposing matrices.

Author(s)

Jonathan Rougier, J.C.Rougier@durham.ac.uk did the faster C implementation.

References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.

See Also

t, to transpose matrices.

Examples

# interchange the first two subscripts on a 3-way array x
x  <- array(1:24, 2:4)
xt <- aperm(x, c(2,1,3))
stopifnot(t(xt[,,2]) == x[,,2],
          t(xt[,,3]) == x[,,3],
          t(xt[,,4]) == x[,,4])

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