Coerce an object to a given class.
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any R object.
the name of the class to which
logical flag. If
The value to use to modify
an optional object
returns the version of this object coerced to be the given
Class. When used in the replacement form on the left of
an assignment, the portion of the object corresponding to
Class is replaced by
The operation of
as() in either form depends on the
definition of coerce methods. Methods are defined automatically
when the two classes are related by inheritance; that is, when
one of the classes is a subclass of the other.
Coerce methods are also predefined for basic classes (including all the types of vectors, functions and a few others).
Beyond these two sources of methods, further methods are defined
by calls to the
setAs function. See that
documentation also for details of how coerce methods work. Use
showMethods(coerce) for a list of all currently defined methods, as in the
Methods are pre-defined for coercing any object to one of the basic
datatypes. For example,
as(x, "numeric") uses the existing
as.numeric function. These and all other existing methods
can be listed as shown in the example.
Chambers, John M. (2016) Extending R, Chapman & Hall. (Chapters 9 and 10.)
If you think of using
try(as(x, cl)), consider
canCoerce(x, cl) instead.
## Show all the existing methods for as() showMethods("coerce")