attributes
All Attributes of an Object
Description
Returns or changes all of the attributes of an object. Attributes specify
the characteristics of any data object.
Usage
attributes(obj)
attributes(obj) <- value
mostattributes(obj) <- value
Arguments
| obj |
any object.
|
| value |
a list object.
|
Details
To explicitly delete all attributes of x, use attributes(x) <- NULL.
When you make an assignment, remember that some attributes accept only certain valid values. See attr
for more information.
The
mostattributes assignment is similar to
attributes, with the following differences.
- The assignment does not result in an explicit error stop for the three special attributes dim, dimnames, and names if the given value is invalid.
(However, the assignment is not made.)
- If the dim attribute is invalid or not given, the dimnames attribute also is not assigned.
- The names attribute can be assigned only when the dim attribute is not assigned.
For other special attributes, such as
tsp,
class, and others,
the
mostattributes assignment requires a valid value. If a valid value is not given,
mostattributes fails with an error. See the examples below for more information.
Value
| attributes(x) | returns a list of all the attributes of x. |
| attributes(x) <- value | returns value. |
| mostattributes(x) <- value | returns value. |
Side Effects
The attributes of x, and generally the class, are changed as a result
of the assignment
version of this function.
The attributes of x are set to the corresponding components of
value and old attributes of x are deleted.
In some cases attributes are mutually exclusive; for example,
assigning names (a
"names" attribute) to a matrix or array
currently erases
"dim" and
"dimnames"
attributes and changes the matrix
or array to a vector.
If value has length 0, all attributes are deleted.
See Also
Examples
m <- lm(y ~ x, data.frame(y=1:4, x=4:1))
attributes(m) # attributes of a linear model
foo <- 1:8
attributes(foo) <- list(dim = c(2,4)) # coerces foo to a matrix
attributes(foo) <- NULL # removes all attributes from foo
attributes(foo) <- list(test="empty_attr", dim= c(2,4),
dimnames= list(LETTERS[1:2], letters[1:4]),
names = paste(1:8))
foo # with all assigned valid attributes.
mostattributes(foo) <- list(test="empty_attr", dim= c(2,4),
dimnames= list(LETTERS[1:2], letters[1:4]),
names = paste(1:8))
foo # with "test" , "dim" and "dimnames" but without "names" even though the names is valid
mostattributes(foo) <- list(test="empty_attr", dim= c(2,3),
dimnames= list(LETTERS[1:2], letters[1:4]),
names = paste(1:8))
foo # with "test" and "names" but without "dim" and "dimnames" since the given "dim" is invalid.
mostattributes(foo) <- list(test="empty_attr", dim= c(2,3),
dimnames= list(LETTERS[1:2], letters[1:8]),
names = paste(1:10))
foo # only with the "test" attribute. The "dim", "dimnames" and "names" are all invalid without error return.