[R] A clean way to initialize class slot of type "numeric" vector
Prof Brian Ripley
ripley at stats.ox.ac.uk
Mon Aug 13 08:22:10 CEST 2007
Well, c() is NULL, so R did as you asked it to. See ?integer: an integer
vector of length 0 can be gotten by integer(0) (and other ways).
If you want integers, why have a slot which is numeric?
> setClass("foo", representation(members="integer"))
An object of class "foo"
is the natural and simpler way to do this.
On Mon, 13 Aug 2007, adschai at optonline.net wrote:
> I have a class definition like this:
> setClass("foo", representation(members="numeric"),
> 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.
> - adschai
> R-help at stat.math.ethz.ch mailing list
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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