[R] A clean way to initialize class slot of type "numeric" vector

[Seth Falcon]

adschai at optonline.net writes:

> Hi,
>
> I have a class definition like this:
>
> setClass("foo", representation(members="numeric"),
> prototype(members=c()))
>
> I intend my class to have members, a slot whose value should be a
> vector of integer. When I initialize this class, I don't have any
> member yet. So my member is blank. But if I run the above definition
> into R, it will complain that my slot members is assigned to NULL
> which does not extend class "numeric". So how can I fix this? Is there
> any clean way to do this? This is quite a common situation but I can't
> seem to find a way out. Any help would be really appreciated. Thank
> you.

How about:

  setClass("foo", representation(members="numeric"),
           prototype(members=numeric(0)))

That is, use a zero-length vector to signify a vector that isn't
there.

+ seth

-- 
Seth Falcon | Computational Biology | Fred Hutchinson Cancer Research Center
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