# 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`

, where`n`

is the number of dimensions of`a`

. When`a`

has named dimnames, it can be a character vector of length`n`

giving a permutation of those names. The default (used whenever`perm`

has 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
# }
```

*Documentation reproduced from package base, version 3.6.1, License: Part of R 3.6.1*