General S4 Class Extractor Functions

A collection and description of functions to extract slots from S4 class objects.

The extractor functions are:

getModel	Extracts the model slot from a S4 object,
getTitle	Extracts the title slot from a S4 object,
getDescription	Extracts the description slot from a S4 object,
getSlot	Extracts a specified slot from a S4 object,
getArgs	Shows the arguments of a S4 function.

Since R version 2.14.0, a generic getCall() is part of R; for earlier versions, we had provided a simple version for S4 objects.

Usage

<!-- % getCall(x, \dots) -->
getModel(object)
getTitle(object)
getDescription(object)

getSlot(object, slotName)

getArgs(f, signature)

Arguments

f

a generic function or the character-string name of one.

object

an object of class S4.

signature

the signature of classes to match to the arguments of f

slotName

a character string, the name of the slot to be extracted from the S4 object.

Value

for getModel, getTitle, getDescription, and getSlot - the content of the corresponding slot.

for getArgs the names of the arguments.

Examples

## Example S4 Representation:
## Hyothesis Testing with Control Settings
setClass("hypTest",
         representation(
             call = "call",
             data = "numeric",
             test = "list",
             description = "character")
         )

## Shapiro Wilk Normaility Test
swTest = function(x, description = "") {
    ans = shapiro.test(x)
    class(ans) = "list"
    new("hypTest",
        call = match.call(),
        data = x,
        test = ans,
        description = description)
}
test = swTest(x = rnorm(500), description = "500 RVs")

## Extractor Functions:
isS4(test)
#> [1] TRUE
getCall(test)
#> swTest(x = rnorm(500), description = "500 RVs")
getDescription(test)
#> [1] "500 RVs"

## get arguments
args(returns)
#> function (x, ...) 
#> NULL
getArgs(returns)
#> returns,:
#> function (x, method = c("continuous", "discrete", "compound", 
#>     "simple"), percentage = FALSE, ...) 
#> NULL
getArgs("returns")
#> returns,:
#> function (x, method = c("continuous", "discrete", "compound", 
#>     "simple"), percentage = FALSE, ...) 
#> NULL
getArgs(returns, "timeSeries")
#> returns,timeSeries:
#> function (x, method = c("continuous", "discrete", "compound", 
#>     "simple"), percentage = FALSE, na.rm = TRUE, trim = TRUE, 
#>     ...) 
#> NULL
getArgs("returns", "timeSeries")
#> returns,timeSeries:
#> function (x, method = c("continuous", "discrete", "compound", 
#>     "simple"), percentage = FALSE, na.rm = TRUE, trim = TRUE, 
#>     ...) 
#> NULL