| dim {base} | R Documentation |
Dimensions of an Object
Description
Retrieve or set the dimension of an object.
Usage
dim(x)
dim(x) <- value
Arguments
x |
an R object, for example a matrix, array or data frame. |
value |
For the default method, either |
Details
The functions dim and dim<- are generic.
dim has a method for data.frames, which returns
the length of the row.names attribute of x and the
length of x (the numbers of “rows” and “columns”).
Value
For an array (and hence in particular, for a matrix) dim retrieves
the dim attribute of the object. It is NULL or a vector
of mode integer.
The replacemnt method changes the "dim" attribute (provided the
new value is compatible) and removes any "dimnames" and
"names" attributes.
References
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth \& Brooks/Cole.
See Also
ncol, nrow and dimnames.
Examples
x <- 1:12 ; dim(x) <- c(3,4)
x
# simple versions of nrow and ncol could be defined as follows
nrow0 <- function(x) dim(x)[1]
ncol0 <- function(x) dim(x)[2]