| InternalMethods {base} | R Documentation |
Many R-internal functions are generic and allow methods to be written for.
The following primitive and internal functions are generic,
i.e., you can write methods for them:
length,
length<-,
lengths,
dimnames,
dimnames<-,
dim,
dim<-,
names,
names<-,
levels<-,
@,
@<-,
as.character,
as.complex,
as.double,
as.integer,
as.logical,
as.raw,
as.vector,
as.call,
as.environment
is.array,
is.matrix,
is.na,
anyNA,
is.nan,
is.finite
is.infinite
is.numeric,
nchar
rep,
rep.int
rep_len
seq.int
(which dispatches methods for "seq"),
is.unsorted
and
xtfrm
In addition, is.name is a synonym for is.symbol and
dispatches methods for the latter. Similarly, as.numeric
is a synonym for as.double and dispatches methods for the
latter, i.e., S3 methods are for as.double, whereas S4 methods
are to be written for as.numeric.
Note that all of the group generic functions are also internal/primitive and allow methods to be written for them.
.S3PrimitiveGenerics is a character vector listing the
primitives which are internal generic and not group generic,
(not only for S3 but also S4).
Similarly, the .internalGenerics character vector contains the names
of the internal (via .Internal(..)) non-primitive functions
which are internally generic.
For efficiency, internal dispatch only occurs on objects, that
is those for which is.object returns true.
methods for the methods which are available.