aperm
Array Transposition
Transpose an array by permuting its dimensions and optionally resizing it.
- Keywords
- array
Usage
aperm(a, perm, …)
# S3 method for default
aperm(a, perm = NULL, resize = TRUE, …)
# S3 method for table
aperm(a, perm = NULL, resize = TRUE, keep.class = TRUE, …)Arguments
- a
the array to be transposed.
- perm
the subscript permutation vector, usually a permutation of the integers
1:n, wherenis the number of dimensions ofa. Whenahas named dimnames, it can be a character vector of lengthngiving a permutation of those names. The default (used wheneverpermhas zero length) 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).- keep.class
logical indicating if the result should be of the same class as
a.- …
potential further arguments of methods.
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.
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
library(base)
# NOT RUN {
# 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])
UCB <- aperm(UCBAdmissions, c(2,1,3))
UCB[1,,]
summary(UCB) # UCB is still a contingency table
# }