Hi Mehmet,
On 11/29/2017 11:22 AM, Suzen, Mehmet wrote:> Hi Herve,
>
> I think you are confusing subclasses and classes. There is no
> contradiction. `is` documentation
> is very clear:
>
> `With one argument, returns all the super-classes of this object's
class.`
Yes that's indeed very clear. So if "list" is a super-class
of "data.frame" (as reported by is(data.frame())), then
is(data.frame(), "list") should be TRUE.
With S4 classes:
setClass("A")
setClass("B", contains="A")
## Get all the super-classes of B.
is(new("B"))
# [1] "B" "A"
## Does a B object inherit from A?
is(new("B"), "A")
# [1] TRUE
Cheers,
H.
>
> Note that object class is always `data.frame` here, check:
>
> > class(data.frame())
> [1] "data.frame"
> > is(data.frame(), "data.frame")
> [1] TRUE
>
> Best,
> Mehmet
>
>
>
>
>
> On 29 Nov 2017 19:13, "Herv? Pag?s" <hpages at fredhutch.org
> <mailto:hpages at fredhutch.org>> wrote:
>
> Hi,
>
> The unary forms of is() and extends() report that data.frame
> extends list, oldClass, and vector:
>
> > is(data.frame())
> [1] "data.frame" "list"
"oldClass" "vector"
>
> > extends("data.frame")
> [1] "data.frame" "list"
"oldClass" "vector"
>
> However, the binary form of is() disagrees:
>
> > is(data.frame(), "list")
> [1] FALSE
> > is(data.frame(), "oldClass")
> [1] FALSE
> > is(data.frame(), "vector")
> [1] FALSE
>
> while the binary form of extends() agrees:
>
> > extends("data.frame", "list")
> [1] TRUE
> > extends("data.frame", "oldClass")
> [1] TRUE
> > extends("data.frame", "vector")
> [1] TRUE
>
> Who is right?
>
> Shouldn't 'is(object, class2)' be equivalent
> to 'class2 %in% is(object)'? Furthermore, is there
> any reason why 'is(object, class2)' is not implemented
> as 'class2 %in% is(object)'?
>
> Thanks,
> H.
>
> --
> Herv? Pag?s
>
> Program in Computational Biology
> Division of Public Health Sciences
> Fred Hutchinson Canc
>
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--
Herv? Pag?s
Program in Computational Biology
Division of Public Health Sciences
Fred Hutchinson Cancer Research Center
1100 Fairview Ave. N, M1-B514
P.O. Box 19024
Seattle, WA 98109-1024
E-mail: hpages at fredhutch.org
Phone: (206) 667-5791
Fax: (206) 667-1319