array {base} | R Documentation

## Multi-way Arrays

### Description

Creates or tests for arrays.

### Usage

    array(data = NA, dim = length(data), dimnames = NULL)
    as.array(x, ...)
    is.array(x)

### Arguments

`data` | a vector (including a list) giving data to fill the array.
`dim` | the dim attribute for the array to be created, that is a vector of length one or more giving the maximal indices in each dimension.
`dimnames` | either `NULL` or the names for the dimensions. This is a list with one component for each dimension, either `NULL` or a character vector of the length given by `dim` for that dimension. The list can be named, and the list names will be used as names for the dimensions. If the list is shorter than the number of dimensions, it is extended by `NULL`s to the length required
`x` | an R object.
`...` | additional arguments to be passed to or from methods.

### Value

`array` returns an array with the extents specified in `dim` and naming information in `dimnames`. The values in `data` are taken to be those in the array with the leftmost subscript moving fastest. If there are too few elements in `data` to fill the array, then the elements in `data` are recycled. If `data` has length zero, `NA` of an appropriate type is used for atomic vectors (`0` for raw vectors) and `NULL` for lists.
`as.array` is a generic function for coercing to arrays. The default method does so by attaching a `dim` attribute to it. It also attaches `dimnames` if `x` has `names`. The sole purpose of this is to make it possible to access the `dim`[names] attribute at a later time.
`is.array` returns `TRUE` or `FALSE` depending on whether its argument is an array (i.e., has a `dim` attribute of positive length) or not. It is generic: you can write methods to handle specific classes of objects, see InternalMethods.

### Note

`is.array` is a primitive function so any argument name is ignored.

### References

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

### See Also

`aperm`, `matrix`, `dim`, `dimnames`.

### Examples

    dim(as.array(letters))
    array(1:3, c(2,4)) # recycle 1:3 "2 2/3 times"
    #     [,1] [,2] [,3] [,4]
    #[1,]    1    3    2    1
    #[2,]    2    1    3    2

[Package base version 2.9.2 Index]