s4

问题 What is a good way of defining a general purpose function which should have implementations for both S3 and S4 classes? I have been using something like this: setGeneric("myfun", function(x, ...){ standardGeneric("myfun"); }); setMethod("myfun", "ANY", function(x, ...) { if(!isS4(x)) { return(UseMethod("myfun")); } stop("No implementation found for class: ", class(x)); }); This succeeds: myfun.bar <- function(x, ...){ return("Object of class bar successfully dispatched."); } object <-

问题 I am trying to build a S4 object by calling the validity method in the constructor. setClass("Person", slot = c(Age = "numeric")) validityPerson<-function(object){ if(object@Age < 0)return("Age cannot be negative") TRUE } setValidity("Person", validityPerson) setMethod("initialize","Person", function(.Object,...){ validObject(.Object) .Object }) This code is problematic because I get new("Person", Age = 12) #Error in if (object@Age < 0) return("Age cannot be negative") : #argument is of

问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: R: show source code of an S4 function in a package I downloaded a package ( GEOquery ) and was playing with some of the functions. One of them is called Table , which, to my understanding, is able to tabulate an S4 dataset. E.g. > summary(GDS2853) # GDS2853 is a dataset I downloaded from NCBI Length Class Mode 1 GDS S4 getAnywhere(Table) shows > getAnywhere(Table) A single object matching ‘Table’ was found It

问题 I'm using the tm package, and looking to get the Flesch-Kincaid scores for a document using R. I found the koRpus package has some a lot of metrics including reading-level, and started using that. However, the object returned seems to be a very complicated s4 object I don't understand how to parse. So, I apply this to my corpus: txt <- system.file("texts", "txt", package = "tm") (d <- Corpus(DirSource(txt, encoding = "UTF-8"), readerControl = list(language = "lat"))) f <- function(x) tokenize

问题 I am writing a small R package with the idea to submit it to Bioconductor in the future, which is why I decided to try out s4 classes. Unfortunately I had problems understanding when I should use setGeneric or not in my package, and the documentation for the setGeneric method is for me more or less incomprehensible. Concrete example: I created a s4 class called Foo I defined a method for the [<- operator using setMethod("[","Foo", ...) I defined a method for the as.list function using

问题 This maybe trivial but I haven't found anything online. Is it possible to create a vector of empty S4 objects in R? Something like: s4Vec<-rep(emptyS4Object,10) Thanks 回答1: Like this: s4Vec <- lapply( rep("yourClass", 10), new ) ? 回答2: I'd be tempted to go with .A <- setClass("A", representation(x="integer")) a <- list(.A())[rep(1, 100)] which makes a single instance (using the convenient generator returned by setClass ) and then replicates that object as R would replicate any other object in

问题 This is borrowed from shiny's function exprToFunction which is used in their reactive function. Actual question How can I delay the evaluation of an expression (e.g. specified via arg expr ) in order to "capture" its content when calling a S4 method (as opposed to a standard R function)? Example Note that x_1 does not exist yet, that's why we want to delay the evaluation of expr and just "capture" its content. Function captureExpression : captureExpression <- function( expr, caller_offset = 1

问题 Actual questions Shouldn't the fact that R6 classes inherit from (informal S3) class R6 allow the definition of S4 methods for signature arguments of that very class? As this is - AFAICT - not the case, what would be a workaround that is in line with current S3/S4 standards or that could somewhat be regarded as "best practice" in such situations? Background and example Reference Classes Consider the following example where you would like to define methods that dispatch on the superclass that

问题 I'm trying to create a method for my class, which inherits from data.frame. I was originally hoping just to inherit the 'show' method from data.frame as well, but I'm also fine with writing my own. I defined my class and 'show' method as follows: setClass("SCvec", representation(auth = "character", dev = "character", sensor = "character", channel = "character", starttime = "character", endtime = "character"), contains="data.frame") setMethod("show", signature(x="SCvec"), function(x) print(x))

问题 This is related to the following post Problems passing arguments with callNextMethod() in R I am writing accessors for two S4 classes, 'foo' and 'bar'. 'bar' inherits from foo and is extended only by a few slots. Instead of writing a full accessor function for objects of class 'bar' I want to pass the arguments to callNextMethod() when accessing a slot that is inherited by 'foo'. My code looks like this: foo <- setClass("foo", representation(x = "numeric", y = "numeric")) bar <- setClass("bar