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 NULL or
a numeric vector, which is coerced to integer (by truncation).
Details
The functions dim and dim<- are internal generic
primitive functions.
dim has a method for data.frame s, which returns
the lengths of the row.names attribute of x and
of x (as the numbers of rows and columns respectively).
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 replacement 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
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]