[R] How to understand whether a class is a S3 class?

[Adrian Waddell]

Megh Dal <megh700004 <at> yahoo.com> writes:

> 
> Hi, is there any way to say: "this class 'x' is a S3 class?" For example what
> is the type of class "data.frame"?
> Is it a S3 class or S4?
> 
> How can I get a complete list of all S3 classes currently available?
> 
> Thanks,
> 
> 


There is the isS4 function

?isS4