ggh4x: Rotate group labels with guide_axis_nested ggplot2

Question

Hello I am using this package I found very handy

So this is the data:

df <- data.frame(
  x = LETTERS[1:16],
  group = rep(c("Group 1", "Group 2", "Group 3"), c(5, 3, 8)),
  value = rpois(16, 10)
)

And this is the code:

ggplot(df, aes(paste0(x, "&", group), value)) +
  geom_col() +
  guides(y = ggh4x::guide_axis_nested(delim = "&")) + coord_flip

This produces this plot:

How can I change the group labels (Group 1, Group 2, and Group 3) to be rotated 90 degrees to the left? Just the group labels.

Answer 1

To style the nested parts of the axis the ggh4x package provides the theme elements ggh4x.axis.nestline.x/y and ggh4x.axis.nesttext.x/y, i.e. to rotate the group labels you could use ggh4x.axis.nesttext.y like so

library(ggplot2)
library(ggh4x)

set.seed(123)

ggplot(df, aes(paste0(x, "&", group), value)) +
  geom_col() +
  guides(y = ggh4x::guide_axis_nested(delim = "&")) +
  coord_flip() +
  theme(
    ggh4x.axis.nesttext.y = element_text(
      angle = 90, hjust = .5
    )
  )