Right align rotated axis title in ggplot2

问题:

How do I right-align the Y-axis title ("Species") with the axis labels (the three species names), such that the axis title is close to the gray panel? hjust does not seem to affect the position.

library(ggplot2)

ggplot(iris,
       aes(x = Species,
           y = Sepal.Width)) +
  geom_boxplot() +
  labs(x = "Species",
      y = "Sepal Width") +
  coord_flip() +
  theme(axis.title.y = element_text(angle = 0, hjust = 0))

回答1:

You can use geom_text together with clip = "off" inside coord_flip() which will allow drawing plot element outside of the plot panel. Obviously you will have to play around with x and y to get the desired output with this manual method

library(ggplot2)

p <- ggplot(iris,
       aes(x = Species,
           y = Sepal.Width)) +
  geom_boxplot() +
  labs(x = NULL,
       y = "Sepal Width") +
  coord_flip(clip = "off") + # add clip = off here
  theme(axis.title.y = element_text(angle = 0, hjust = 0))

p +
  # add axis title here
  geom_text(
    x = 3.5,
    y = 1.85,
    inherit.aes = FALSE,
    label = "Species",
    check_overlap = TRUE,
    hjust = 1,
    fontface = 'bold',
    size = 5
  ) +
  theme(plot.margin = unit(c(1, 1, 1, 2), "lines"))

^{Created on 2018-10-27 by the reprex package (v0.2.1)}