| 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 |
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 |
x |
an R object. |
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() coerces its argument to be an array 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.
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