R help - Jul 2011 - Simple inheritance check fails (integer from numeric)

Dear list,

In a function, I don't care if my input has class 'integer' or 
'numeric', so I wanted to use 'inherits()' to control for that.

However, this function tells me that an actual object of class 'integer'
does not inherit from class 'numeric'. The class def of
'integer' does
state 'numeric' as one of the superclasses. Isn't that somewhat 
inconsistent?

 > getClass("integer")
Class "integer" [package "methods"]

No Slots, prototype of class "integer"

Extends: "numeric", "vector",
"data.frameRowLabels"

 > a <- 1:3
 > class(a)
[1] "integer"

 > inherits(a, "numeric")
[1] FALSE

Regards,
Janko

On Jul 7, 2011, at 6:01 AM, Janko Thyson wrote:
> Dear list,
>
> In a function, I don't care if my input has class 'integer' or
> 'numeric', so I wanted to use 'inherits()' to control for
that.
>
> However, this function tells me that an actual object of class  
> 'integer' does not inherit from class 'numeric'. The class
def of
> 'integer' does state 'numeric' as one of the superclasses.
Isn't
> that somewhat inconsistent?
>
> > getClass("integer")
> Class "integer" [package "methods"]
>
> No Slots, prototype of class "integer"
>
> Extends: "numeric", "vector",
"data.frameRowLabels"
>
> > a <- 1:3
> > class(a)
> [1] "integer"
>
> > inherits(a, "numeric")
> [1] FALSE
>
 > a <- 1:3
 > is.numeric(a)
[1] TRUE

-- 
David Winsemius, MD
West Hartford, CT