[R] VERY basic question about S4 classes

[Duncan Murdoch]

On 21/04/2010 7:00 AM, Albert-Jan Roskam wrote:
> Hi,
>  
> I'm new to R and S4 classes. I defined a class with two methods (myMethod1 and myMethod2). I want to call myMethod1 within myMethod2. Why does the code below not work? The name 'myMethod1' doesn't appear to have meaning inside myMethod2, even though the two methods belong to the same class.
>  
>  
> setClass(Class="SomeClass",
>      representation=representation(
>       amount="numeric")
> )
> setGeneric (name="myMethod1",
>   def=function(object){standardGeneric("myMethod1")}
> )
> setMethod(f = "myMethod1",
>  signature = "SomeClass",
>  definition=function(object) {print(object at amount)}
> )
> setGeneric(name="myMethod2",
>   def=function(object){standardGeneric("myMethod2")}
> )
> setMethod(f = "myMethod2",
>  signature = "SomeClass",
>  definition=function(object) {print(myMethod1 * 2)}
>   

You should have used myMethod1(object), not just myMethod1.

Duncan Murdoch

> )
> instance <- new(Class="SomeClass", amount=10)
> myMethod1(instance) # prints '10'
> myMethod2(instance) # ERROR: is supposed to print '20'
>
> Thank you in advance for your help!
>
> Cheers!!
> Albert-Jan
>
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