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 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]