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Given an arbitrary R object, how can I obtain all the methods associated with the object?
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(See also the draft 'R Language Definition'.) UseMethod creates a new function call with arguments matched as they came in to the generic. Any local variables defined before the call to UseMethod are retained (unlike S). Any statements after the call to UseMethod will not be evaluated as UseMethod does not return.
To determine the class of any R object's “internal” type, use the class() function. If the object does not have a class attribute, it has an implicit class, prominently “matrix“, “array“, “function” or “numeric,” or the result of typeof(x). The class() function is robust.
The class() function in R is used to return the values of the class attribute of an R object.
The S3 and S4 software in R are two generations implementing functional object-oriented programming. S3 is the original, simpler for initial programming but less general, less formal and less open to validation. The S4 formal methods and classes provide these features but require more programming.
The closest I can think of is methods (if S3 object/function, List all available methods for an S3 generic function, or all methods for a class.), or showMethods (if S4).
e.g.:
> A <- matrix(runif(10)) > B <- methods(class=class(A)) > B [1] anyDuplicated.matrix as.data.frame.matrix as.raster.matrix* [4] boxplot.matrix determinant.matrix duplicated.matrix [7] edit.matrix* head.matrix isSymmetric.matrix [10] relist.matrix* subset.matrix summary.matrix [13] tail.matrix unique.matrix Non-visible functions are asterisked > attr(B,'info') visible from anyDuplicated.matrix TRUE package:base as.data.frame.matrix TRUE package:base as.raster.matrix FALSE registered S3method boxplot.matrix TRUE package:graphics determinant.matrix TRUE package:base duplicated.matrix TRUE package:base edit.matrix FALSE registered S3method head.matrix TRUE package:utils isSymmetric.matrix TRUE package:base relist.matrix FALSE registered S3method subset.matrix TRUE package:base summary.matrix TRUE package:base tail.matrix TRUE package:utils unique.matrix TRUE package:base Or for a function:
> methods(summary) [1] summary.aov summary.aovlist summary.aspell* [4] summary.connection summary.data.frame summary.Date [7] summary.default summary.ecdf* summary.factor [10] summary.glm summary.infl summary.lm [13] summary.loess* summary.manova summary.matrix [16] summary.mlm summary.nls* summary.packageStatus* [19] summary.PDF_Dictionary* summary.PDF_Stream* summary.POSIXct [22] summary.POSIXlt summary.ppr* summary.prcomp* [25] summary.princomp* summary.srcfile summary.srcref [28] summary.stepfun summary.stl* summary.table [31] summary.tukeysmooth* Non-visible functions are asterisked ?Methods may also prove a useful read.
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