| plot.factor {graphics} | R Documentation | 
This functions implements a “scatterplot” method for
factor arguments of the generic
plot function.
Actually, boxplot is used when y is numeric
and a spineplot when y is a factor. For 
a single factor x (i.e., with y missing) a simple
barplot is produced.
## S3 method for class 'factor': plot(x, y, legend.text = NULL, ...)
x, y | 
numeric or factor. y may be missing. | 
legend.text | 
character vector for annotation of y axis,
defaults to levels(y). Can be used instead of yaxlabels
(for backward compatibility). | 
... | 
Further arguments to plot, see also
par. | 
plot.default, plot.formula,
barplot, boxplot, spineplot.
plot(PlantGrowth)                                # -> plot.data.frame
plot(weight ~ group, data = PlantGrowth)         # numeric vector ~ factor
plot(cut(weight, 2) ~ group, data = PlantGrowth) # factor ~ factor
## passing "..." to spineplot() eventually:
plot(cut(weight, 3) ~ group, data = PlantGrowth,
     col = hcl(c(0, 120, 240), 50, 70))
plot(PlantGrowth$group, axes=FALSE, main="no axes")# extremly silly