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, "Hervé Pagès" <hpa...@fredhutch.org
<mailto:hpa...@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.
--
Hervé Pagès
Program in Computational Biology
Division of Public Health Sciences
Fred Hutchinson Canc
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Hervé Pagès
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: hpa...@fredhutch.org
Phone: (206) 667-5791
Fax: (206) 667-1319
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