class(x) class(x) <- value unclass(x)
x
.
class
returns the class of the object
x
as a character string.
class
sets the class of its argument
to the string on the right of the assignment. This is used in functions that
create objects from objects of a particular class. In this case,
x
should
be a prototype for the intended class. If you want to coerce
x
to be a
of a particular class, use the
as
function instead.
unclass
returns the representation of
x
as an object with the class of
the prototype for
class(x)
. If
x
has a representation with slots,
unclass(x)
returns a named list or structure, containing the slots in that
representation. Otherwise,
unclass(x)
returns an object of the same class
as the prototype of the class.
oldClass
to retrieve and set classes for old-style
objects in which the class has no representation and may have more than
one character string in the value.
The class of an object is used to decide which method of a
generic function is to be used in a given instance.
Functions may use
unclass
in order to deal with an object in raw form
without any assistance from methods that may be available to process that class.
Setting
class(x)
to
NULL
is
equivalent (for backward compatibility) but is now deprecated; it will not
actually set the class to
NULL
because all objects are now classed.
Assigning a class to an object is a primitive operation.
Assigning class
"matrix"
to object
x
, for example, does
notcause
x
to be coerced to have all the attributes of a matrix object:
if you wanted that to happen, use
as.matrix(x)
.
Similarly,
class
is not a generic function and methods cannot be
written for it.
class(state.x77) # returns "matrix" class(state.name) # returns "character"