dimnames {base}R Documentation

Dimnames of an Object


Retrieve or set the dimnames of an object.


dimnames(x) <- value


x an R object, for example a matrix, array or data frame.
value a possible value for dimnames(x): see “Value”.


The functions dimnames and dimnames<- are generic.

For an array (and hence in particular, for a matrix), they retrieve or set the dimnames attribute (see attributes) of the object. The list value can have names, and these will be used to label the dimensions of the array where appropriate.

Both have methods for data frames. The dimnames of a data frame are its row.names attribute and its names.

As from R 1.8.0 factor components of value will be coerced to character.


The dimnames of a matrix or array can be NULL or a list of the same length as dim(x). If a list, its components are either NULL or a character vector the length of the appropriate dimension of x.


Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.

See Also

rownames, colnames; array, matrix, data.frame.


## simple versions of rownames and colnames
## could be defined as follows
rownames0 <- function(x) dimnames(x)[[1]]
colnames0 <- function(x) dimnames(x)[[2]]

[Package base version 2.1.0 Index]