attr(x, which, exact = FALSE)
attr(x, which) <- value
which
be matched exactly?NULL
to remove the attribute. The extraction function first looks for an exact match to which
amongst the attributes of x
, then (unless exact = TRUE
)
a unique partial match.
(Setting options(warnPartialMatchAttr = TRUE)
causes
partial matches to give warnings.)
The replacement function only uses exact matches.
Note that some attributes (namely class
,
comment
, dim
, dimnames
,
names
, row.names
and
tsp
) are treated specially and have restrictions on
the values which can be set. (Note that this is not true of
levels
which should be set for factors via the
levels
replacement function.)
The extractor function allows (and does not match) empty and missing
values of which
: the replacement function does not.
Both are primitive functions.
attributes
# create a 2 by 5 matrix
x <- 1:10
attr(x,"dim") <- c(2, 5)
Run the code above in your browser using DataLab