| Methods {base} | R Documentation |
Many R-internal functions are generic and allow
methods to be written for. Group methods in particular are
available for the "Math", "Ops", and
"Summary" group.
Math.data.frame(x, ...) Math.factor(x, ...) Ops.data.frame(e1, e2 = NULL) Ops.factor(e1, e2) Ops.ordered(e1, e2) Summary.data.frame(x, ...) Summary.factor(x, ...) .Method .Generic .Group .Class
There are three groups for which methods can be written, namely
the "Math", "Ops" and "Summary" groups.
A function f belonging to one of these groups must be
.Internal or .Primitive and will
automatically be using <grp>.<class> (ob) when
f(<ob>) is called, f belongs to group
<grp> and <ob> is of class
<class>.
"Math":
abs, sign, sqrt, floor, ceiling, trunc,round, signif
exp, log, cos, sin, tan,acos, asin, atan
cosh, sinh, tanh,
acosh, asinh, atanh
lgamma, gamma, gammaCody,digamma, trigamma, tetragamma,
pentagamma
cumsum, cumprod, cummax, cummin
"Ops":
"+", "-", "*", "/",
"^", "%%", "%/%"
"&", "|", "!"
"==", "!=",
"<", "<=", ">=", ">"
"Summary":
all, any
sum, prod
min, max
The following builtin functions are generic as well, i.e., you
can write methods for them:
dimnames<-,
dimnames,
dim<-,
dim
c,
unlist,
as.vector,
is.na,
is.nan
Appendix A, Classes and Methods of
Chambers, J. M. and Hastie, T. J. eds (1992)
Statistical Models in S.
Wadsworth & Brooks/Cole.
methods for methods of non-Internal generic functions.
methods("Math")
methods("Ops")
methods("Summary")
d.fr <- data.frame(x=1:9, y=rnorm(9))
data.class(1 + d.fr) == "data.frame" ##-- add to d.f. ...