facet_wrap_labeller: A function to allow for expressions in ggplot facet titles.
In johnDorian/ggsnippets: A few addons for the ggplot2 package

Description Usage Arguments Details Value References See Also Examples

Allows for the use of expressions with facet titles.

1	facet_wrap_labeller(gg.plot, labels = NULL)

`gg.plot`	a ggplot object
`labels`	labels for each facet.

A function to label facetted ggplots

This function alters the lables of a facetted ggplot object. This is useful if you want use expressions or have a simple way to mdify the labels of a facetted ggplot object.

a ggplot object with new facet titles.

http://stackoverflow.com/questions/11979017

plotmath

## Add a factor to the cars example data to facet the plots
library(ggplot2)
x_cars <- data.frame(cars, variable = sample(letters[1:5],
                                             50,
                                             replace = TRUE))
## Create the plot with facets
plt <- ggplot() + geom_point(aes(speed, dist), x_cars) +
       facet_wrap(~variable, ncol=1)
plt
## An example without labels - no real point in this.
library(gridExtra)
facet_wrap_labeller(plt)
## Adding expressions within the facet labels.
facet_wrap_labeller(plt, labels = c(expression(a^2),
                                   expression(b[1]),
                                   expression(frac(c,2)),
                                    "d",
                                     expression(infinity)))