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 `NULL` or
a numeric vector, which is coerced to integer (by truncation). |

### Details

The functions `dim`

and `dim<-`

are generic.

`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).

These functions are primitive, so argument names are ignored
(but this might not be true of their methods).

### 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

`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]

[Package

*base* version 2.10.1

Index]