Changing one character in axis tick labels to italic while keeping multiple lines

Question

I have a geom_col from ggplot2 with labels for categorical axis ticks like below:

That plot was created with the following code:

library(tidyverse)

samplecounts=as.data.frame(c(1:4))
samplecounts$variable2=c("cat1","cat2","cat3","cat4")
names(samplecounts)[1]="variable1"

my.labels=c("Count category 1\n(n=1)","Count 2 of a different length\n(n=1)",
            "Countegory 3\n(n=1)","Count 4 cat\n(n=1)")

a=ggplot(data=samplecounts,aes(variable2,variable1))+
  geom_col(color='black')+
  scale_x_discrete(labels=my.labels) +
  coord_flip()
a

My goal is to italicize only the "n" character in each of the axis tick labels. I have seen solutions for doing this in the axis title. In this case, the axis title is "variable2". I am looking to change the axis tick labels, "Count category 4 (n=1), etc.".

Side note, the italics function does not exist in my current version of R. I am running R 4.0.2.

Answer 1

Try with ggtext package and adding ** to your text chains and using element_mardown() in your theme like this (Updated: In markdown language break lines use <br> instead on \n):

library(tidyverse)
library(ggtext)
#Data
samplecounts=as.data.frame(c(1:4))
samplecounts$variable2=c("cat1","cat2","cat3","cat4")
names(samplecounts)[1]="variable1"

my.labels=c("Count category 1<br>*(n=1)*","Count 2 of a different length<br>*(n=1)*",
            "Countegory 3<br>(*n=1*)","Count 4 cat<br>*(n=1)*")
#Plot
ggplot(data=samplecounts,aes(variable2,variable1))+
  geom_col(color='black')+
  scale_x_discrete(labels=my.labels) +
  theme(axis.text.y = element_markdown())+
  coord_flip()

Output: