| attributes {base} | R Documentation |
These functions access an object's attributes. The first form below returns the object's attribute list. The replacement forms uses the list on the right-hand side of the assignment as the object's attributes (if appropriate).
attributes(obj) attributes(obj) <- value mostattributes(obj) <- value
obj |
an object |
value |
an appropriate named list of attributes, or NULL. |
Note that some attributes (namely class,
comment, dim, dimnames,
names, (from R 2.4.0) row.names and
tsp) are treated specially and have restrictions on
the values which can be set.
Attributes are not stored internally as a list and should be thought
of as a set and not a vector. They must have unique
names (and NA is taken as "NA", not a missing value).
The mostattributes assignment takes special care for the
dim, names and dimnames
attributes, and assigns them only when valid whereas an
attributes assignment would give an error if any are not.
The names of a pairlist are not stored as attributes, but are reported as if they were (and can be set by the replacement method for attributes).
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
attr.
x <- cbind(a=1:3, pi=pi) # simple matrix w/ dimnames
attributes(x)
## strip an object's attributes:
attributes(x) <- NULL
x # now just a vector of length 6
mostattributes(x) <- list(mycomment = "really special", dim = 3:2,
dimnames = list(LETTERS[1:3], letters[1:5]), names = paste(1:6))
x # dim(), but not {dim}names