Use label_both() with expression-CodePudding

From ggplot2's reference manual, of label_both:

library(ggplot2)
mtcars$cyl2 <- factor(mtcars$cyl, labels = c("alpha", "beta", "gamma"))
p <- ggplot(mtcars, aes(wt, mpg))   geom_point()

# Displaying both the values and the variables
p   facet_grid(. ~ cyl, labeller = label_both)

This will give us facet strips with both variable name and its values. However, say if I want to change the appearance of the variable name, but not change the values, e.g.:

expression(italic(cyl))

So that I can get a cyl: 4 instead of cyl: 4, is it possible to do it using the labeller function?

CodePudding user response：

After a look at the docs and the source code label_both has no parse option. But similar to the approach in the answer referenced by @jared_mamrot in his comment you could use as_labeller to create a custom labeller for which you use label_parsed.

library(ggplot2)

mtcars$cyl2 <- factor(mtcars$cyl, labels = c("alpha", "beta", "gamma"))
p <- ggplot(mtcars, aes(wt, mpg))  
  geom_point()

p   facet_grid(. ~ cyl,
  labeller = as_labeller(
      ~ paste0("italic(cyl):", .x), label_parsed
  )
)