# R: Show all the methods for the specified function(s)

showMethods {methods} | R Documentation

## Show all the methods for the specified function(s)

### Description

Show a summary of the methods for one or more generic functions, possibly restricted to those involving specified classes.

### Usage

    showMethods(f = character(), where = topenv(parent.frame()),
                classes = NULL, includeDefs = FALSE, inherited = !includeDefs,
                showEmpty, printTo = stdout())

### Arguments

`f` | one or more function names. If omitted, all functions will be shown that match the other arguments.
`where` | Used only when `f` is missing, or length 0, to determine which generic functions to examine. If `where` is supplied, only the generic functions returned by `getGenerics(where)` are eligible for printing. If `where` is also missing, all the cached generic functions are considered.
`classes` | If argument `classes` is supplied, it is a vector of class names that restricts the displayed results to those methods whose signatures include one or more of those classes.
`includeDefs` | If `includeDefs` is `TRUE`, include the definitions of the individual methods in the printout.
`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 `selectMethod` if you want to know what method is dispatched for particular classes of arguments.
`showEmpty` | logical indicating whether methods with no defined methods matching the other criteria should be shown at all. By default, `TRUE` if and only if argument `f` is not missing.
`printTo` | The connection on which the printed information will be written; by default, standard output. If `printTo` is `FALSE`, the output will be collected as a character vector and returned as the value of the call to `showMethod`. See `show`.

### Details

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.

### Value

If `printTo` is `FALSE`, the character vector that would have been printed is returned; otherwise the value is the connection or filename, via `invisible`.

### References

The R package methods implements, with a few exceptions, the programming interface for classes and methods in the book Programming with Data (John M. Chambers, Springer, 1998), in particular sections 1.6, 2.7, 2.8, and chapters 7 and 8.

While the programming interface for the methods package follows the reference, the R software is an original implementation, so details in the reference that reflect the S4 implementation may appear differently in R. Also, there are extensions to the programming interface developed more recently than the reference. See `Methods` and references from there.

### See Also

`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.

### Examples

    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
    ## End(Not run)

    not.there <- !any("package:stats4" == search())
    if(not.there) library(stats4)
    showMethods(classes = "mle")
    if(not.there) detach("package:stats4")

[Package methods version 2.6.0 Index]