row/colnames {base} | R Documentation |
Retrieve or set the row or column names of a matrix-like object.
rownames(x, do.NULL = TRUE, prefix = "row") rownames(x) <- value colnames(x, do.NULL = TRUE, prefix = "col") colnames(x) <- value
x |
a matrix-like R object, with at least two dimensions for
colnames . |
do.NULL |
logical. Should this create names if they are
NULL ? |
prefix |
for created names. |
value |
a valid value for that component of
dimnames(x) . For a matrix or array this is either
NULL or a character vector of length the appropriate
dimension. |
The extractor functions try to do something sensible for any
matrix-like object x
. If the object has dimnames
the first component is used as the row names, and the second component
(if any) is used for the col names. For a data frame, rownames
and colnames
are equivalent to row.names
and
names
respectively.
If do.NULL
is FALSE
, a character vector (of length
NROW(x)
or NCOL(x)
) is returned in any
case, prepending prefix
to simple numbers, if there are no
dimnames or the corresponding component of the dimnames is NULL
.
For a data frame, value
for rownames
should be a
character vector of unique names, and for colnames
a character
vector of unique syntactically-valid names. (Note: uniqueness and
validity are not enforced.)
dimnames
,
case.names
,
variable.names
.
m0 <- matrix(NA, 4, 0) rownames(m0) m2 <- cbind(1,1:4) colnames(m2, do.NULL = FALSE) colnames(m2) <- c("x","Y") rownames(m2) <- rownames(m2, do.NULL = FALSE, prefix = "Obs.") m2