pscategorical: Add a categorical position scale to the plot

In hadley/ggplot1: Before there was ggplot2

Description

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).

Usage

pscategorical(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

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.

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

hadley/ggplot1 documentation built on Aug. 19, 2019, 2:42 p.m.