[R] Weird problem with median on a factor
Prof Brian Ripley
ripley at stats.ox.ac.uk
Mon Nov 3 17:45:36 CET 2003
On Mon, 3 Nov 2003 RBaskin at ahrq.gov wrote:
> Continuing to beat the greasy spot in the road where the dead horse used to
> 1) I know that the people building r are working on bigger and better things
> than this silly question and I appreciate the existence of this complicated
> package that was dropped in my lap for free.
> 2) Tony Platt succinctly pointed out one of the underlying 'problems'
> (possibly in my understanding):
> > #this is a perfectly reasonable r object
> > some.weird.object<-factor(c("a","b","c"))
> > #this is an internal r function acting on an object
> > typeof(some.weird.object)
>  "integer"
> > #this is a primitive r function acting on an object
> > is.numeric(some.weird.object)
>  FALSE
> Do these functions behave in a design consistent manor?? Can a single r
> object simultaneously be of type integer and NOT numeric?? If this is
> intentional can someone explain why?
See the help for is.numeric: it *does* explain this. You should be
careful not to confuse classes with representations.
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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