italicise_certain_facet_labels.R

# quick and dirty example of not italicising the whole label.

# Italicise certain words only in facet labels in ggplot2
library(tidyverse)

# create random data frame
species <- c('Chlorella sp.', 'Buteo buteo')

d <- tibble(species = species) %>%
  group_by(species) %>%
  do(data.frame(x = 1:5, y = 1:5)) %>%
  ungroup()

ggplot(d, aes(x, y)) +
  geom_point() +
  facet_wrap(~species) +
  theme(strip.text = element_text(face = "italic"))

# want only certain word to be italics
# add expression to be parsed into the dataframe

# use case_when for each facet label in the dataframe.
d <- mutate(d, facet_lab = case_when(species == 'Chlorella sp.' ~ 'expression(italic("Chlorella")~sp.)',
                                     species == 'Buteo buteo' ~ 'expression(italic("Buteo buteo"))'))
d <- mutate(d, facet_lab = case_when(species == 'Chlorella sp.' ~ 'italic("Chlorella")~sp.',
                                     species == 'Buteo buteo' ~ 'italic("Buteo buteo")'))

# plot
ggplot(d, aes(x, y)) +
  geom_point() +
  facet_wrap(~facet_lab, labeller = label_parsed)


# https://gist.github.com/54ec4d6cb76fb5eced5f305d043638af