[R] Histogram for factors

[Robert Gentleman]

On Sat, Jan 13, 2001 at 10:31:16AM +0100, Martin Maechler wrote:
> >>>>> "PD" == Peter Dalgaard BSA <p.dalgaard at biostat.ku.dk> writes:
> 
>     PD> Thomas Vogels <tov at ece.cmu.edu> writes:
>     >> Hi,
>     >> 
>     >> I keep running into this:
>     R> hist (f)
>     >> Error in hist.default(f) : `x' must be numeric
>     >> 
>     >> To which of course something like (simplified but not beyond
>     >> repair):
>     R> hist.factor <- function (ff) {
>     >> jj <- table (ff) jb <- barplot (jj, ylab="Frequency",
>     >> xlab=deparse(substitute(ff))) axis (1, jb, names (jj)) }
>     R> hist (f)
>     >> is a possible solution.
>     >> 
>     >> Why is a 'hist.factor' not part of the base distribution?  Is this
>     >> kind of thing discouraged?  Usually not needed?  Am I missing sth
>     >> else?
> 
>     PD> Well histograms are density estimates defined for continuous
>     PD> variables. What you're drawing is a barplot. barplot.factor might
>     PD> be a good idea, though.
> 
> Well,
> 	plot(f) 
> already draws a barplot of a factor f (by the  plot.factor method).

  Which many of us would think of as being the right "default" plot
for a factor. However, I also think that the right thing for histogram
to do is to inform you that this is not a continuous variable.
I don't think of a barplot (barchart) as a specialized histogram.
 
> 
> Martin
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