showMethods | R Documentation |
Show a summary of the methods for one or more generic functions, possibly restricted to those involving specified classes.
showMethods(f = character(), where = topenv(parent.frame()), classes = NULL, includeDefs = FALSE, inherited = !includeDefs, showEmpty, printTo = stdout(), fdef) .S4methods(generic.function, class)
f |
one or more function names. If omitted, all functions will be shown that match the other arguments. The argument can also be an expression that evaluates to a single
generic function, in which
case argument |
where |
Where to find the generic function, if not supplied as an
argument. When |
classes |
If argument |
includeDefs |
If |
inherited |
logical indicating if methods that have been found by
inheritance, so far in the session, will be included and marked as
inherited. Note that an inherited method will not usually appear
until it has been used in this session. See
|
showEmpty |
logical indicating whether methods with no defined
methods matching the other criteria should be shown at all. By
default, |
printTo |
The connection on which the information will be shown; by default, on standard output. |
fdef |
Optionally, the generic function definition to use; if
missing, one is found, looking in |
generic.function, class |
See |
See methods
for a description of .S4methods
.
The name and package of the generic are followed by the list of signatures for which methods are currently defined, according to the criteria determined by the various arguments. Note that the package refers to the source of the generic function. Individual methods for that generic can come from other packages as well.
When more than one generic function is involved, either as specified or
because f
was missing, the functions are found and
showMethods
is recalled for each, including the generic as the
argument fdef
. In complicated situations, this can avoid some
anomalous results.
If printTo
is FALSE
, the character vector that would
have been printed is returned; otherwise the value is the connection
or filename, via invisible
.
Chambers, John M. (2008) Software for Data Analysis: Programming with R Springer. (For the R version.)
Chambers, John M. (1998) Programming with Data Springer (For the original S4 version.)
setMethod
, and GenericFunctions
for other tools involving methods;
selectMethod
will show you the method dispatched for a
particular function and signature of classes for the arguments.
methods
provides method discovery tools for light-weight
interactive use.
require(graphics) ## Assuming the methods for plot ## are set up as in the example of help(setMethod), ## print (without definitions) the methods that involve class "track": showMethods("plot", classes = "track") ## Not run: # Function "plot": # x = ANY, y = track # x = track, y = missing # x = track, y = ANY require("Matrix") showMethods("%*%")# many! methods(class = "Matrix")# nothing showMethods(class = "Matrix")# everything showMethods(Matrix:::isDiagonal) # a non-exported generic ## End(Not run) if(no4 <- is.na(match("stats4", loadedNamespaces()))) loadNamespace("stats4") showMethods(classes = "mle") # -> a method for show() if(no4) unloadNamespace("stats4")
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