dim {base} | R Documentation |
Retrieve or set the dimension of an object.
dim(x)
dim(x) <- value
x |
an R object, for example a matrix, array or data frame. |
value |
for the default method, either |
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).
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.
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
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]