On 10 Nov 2000, Peter Dalgaard BSA wrote:
> Jonathan Rougier <J.C.Rougier@durham.ac.uk> writes:
>
> > Can I suggest that in cov and cor the lines
> >
> > if (is.data.frame(x))
> > x <- as.matrix(x)
> > if (is.data.frame(y))
> > y <- as.matrix(y)
> >
> > be replaced by
> >
> > if (is.data.frame(x))
> > x <- data.matrix(x) # coerce logical and factors
> > if (is.data.frame(y))
> > y <- data.matrix(y) # likewise
>
> I'd oppose that, especially for factors. Correlations between factors
> are as likely to be nonsens as remotely meaningful.
I agree with that. I was thinking that a warning would be
helpful. Perhaps something along the lines of
if (any(sapply(x, is.factor))) warning("Coercing factor to numeric")
J.
Jonathan Rougier Science Laboratories
Department of Mathematical Sciences South Road
University of Durham Durham DH1 3LE
http://www.maths.dur.ac.uk/stats/people/jcr/jcr.html
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