pscategorical {ggplot}R Documentation

Position: categorical

Description

Add a categorical position scale to the plot

Usage

pscategorical(plot = .PLOT, variable="x", name="", expand=c(0.01, 0.6))

Arguments

plot ggplot object
variable axis ("x" or "y")
name name of the scale (used in the legend)
expand expansion vector (numeric vector, multiplicative and additive expansion). Defaults to adding 0.6 on either end of the scale.

Details

A categorical scale converts a factor into a numerical representation very simply: by using as.numeric. This means that levels will be placed a integer locations in the same order that they appear in the levels of the factor (see levels).

If you want to reorder (or combine) categories, currently the best way to do this is to modify the original factors. In a future version of ggplot I will probably expand the categorical scale so that you can do that here.

This scale is added to the plot automatically when you use a categorical variable in the x or y aesthetics. You shouldn't need to to call this function unless (for some reason) you want to change the expansion factor.

Author(s)

Hadley Wickham <h.wickham@gmail.com>

Examples

p <- ggpoint(ggplot(mtcars, aesthetics=list(x=cyl, y=mpg)))
pscategorical(p, "x") # no change, because already categorical
pscategorical(p, "y") # chops into discrete segments

[Package ggplot version 0.4.2 Index]