ggplot2 (version 1.0.0)

labeller: Generic labeller function for facets

Description

One-step function for providing methods or named character vectors for displaying labels in facets.

Usage

labeller(..., keep.as.numeric = FALSE)

Arguments

...

Named arguments of the form variable=values, where values could be a vector or method.

keep.as.numeric

logical, default TRUE. When FALSE, converts numeric values supplied as margins to the facet to characters.

Value

• Function to supply to facet_grid for the argument labeller.

Details

The provided methods are checked for number of arguments. If the provided method takes less than two (e.g. capitalize), the method is passed values. Else (e.g. label_both), it is passed variable and values (in that order). If you want to be certain, use e.g. an anonymous function. If errors are returned such as ``argument ".." is missing, with no default'' or ``unused argument (variable)'', matching the method's arguments does not work as expected; make a wrapper function.

Examples

p1 <- ggplot(mpg, aes(cty, hwy)) + geom_point()
p1 + facet_grid(cyl ~ class, labeller=label_both)
p1 + facet_grid(cyl ~ class, labeller=labeller(cyl=label_both))

ggplot(mtcars, aes(x = mpg, y = wt)) + geom_point() +
  facet_grid(vs + am ~ gear, margins=TRUE,
             labeller=labeller(vs=label_both, am=label_both))

capitalize <- function(string) {
  substr(string, 1, 1) <- toupper(substr(string, 1, 1))
  string
}
conservation_status <- c('cd'='Conservation Dependent',
                         'en'='Endangered',
                         'lc'='Least concern',
                         'nt'='Near Threatened',
                         'vu'='Vulnerable',
                         'domesticated'='Domesticated')
## Source: http://en.wikipedia.org/wiki/Wikipedia:Conservation_status

p2 <- ggplot(msleep, aes(x=sleep_total, y=awake)) + geom_point()
p2 + facet_grid(vore ~ conservation, labeller = labeller(vore = capitalize))

p2 + facet_grid(vore ~ conservation,
  labeller=labeller(vore = capitalize, conservation = conservation_status ))

# We could of course have renamed the levels;
# then we can apply another nifty function
msleep$conservation2 <- plyr::revalue(msleep$conservation, conservation_status)

p2 %+% msleep +
  facet_grid(vore ~ conservation2, labeller = labeller(vore = capitalize))
p2 %+% msleep +
 facet_grid(vore ~ conservation2, labeller = labeller(conservation2 =
 label_wrap_gen(10)))