dimnames attribute of an array.
This is a list of the same length as the dimension of the array.
dimnames(x) dimnames(x) <- value
dim(x), or
NULL,
whose components have length equal to the corresponding dimension or zero.
x if they exist, or
NULL.
dimnames of an object is a list whose length is
length(dim(x)).
The
ith element of
dimnames(x) is either of length
0 (not allowed
for data frames or
bdFrames)
or is a vector of
dim(x)[i]
character strings, and in the latter case should be
thought of
as a set of labels for the
ith dimension of
x.
dimnames attribute of
x is created
or changed if
x is an array or data frame and
value is
compatible with
dim(x).
This is a generic function, there is a method for data frames and
bdFrames.
Arrays (may) have a
dimnames attribute, and this is what is
reported on or changed.
The dimnames of a data frame or
bdFrame are the
row.names attribute and the
names
of the object.
To explicitly delete the
dimnames attribute of an array (or matrix),
use
dimnames(x)<-NULL.
To explicitly delete row or column names, see example below.
You may not remove the
dimnames of a data frame or
bdFrame.
The row and column
names must have the same length as the number or rows
and columns of the data frame or
bdFrame.
Column names must be unique;
row names must be unique unless the data frame or
bdFrame has a
non-
NULL
dup.row.names
attribute.
The
value may be a character vector, or anything that
can be coerced to a character vector. However, it should not
be a
bdCharacter or other
bdVector;
you can convert these to an ordinary vector using
bd.coerce
Instead of using
names to replace row names from a matrix,
use
rowIds or
dimnames.
Array subscripts retain
dimnames; see
Subscript.
dimnames(iris)[[3]] # iris species
my.matrix <- matrix(1:12, 3)
dimnames(my.matrix) <- list(NULL, c("red", "blue", "brown", "green"))
dimnames(my.matrix)[[1]] <- c("a", "b", "c") # add row names
dimnames(my.matrix)[[1]] <- character(0) # remove row names
dimnames(my.matrix)[[2]] <- c("d", "e", "f", "g") # change col names
# Note -- when creating dimnames initially you may use NULL as
# as a shortcut for character(0), but not when modifying dimnames.
# This is illegal: dimnames(my.matrix)[[1]] <- NULL