How to rotate category title with facet

look at my code:

library(ggplot2)

ggplot(mpg, aes(displ, hwy))  
  geom_point()  
  facet_wrap(vars(class))

How to rotate the title of each category (2seater, compact etc), to place them on the right and horizontal?

CodePudding user response：

You could place the strip text on the right via the strip.position argument of facet_wrap and make them horizontal via the theme option strip.text.y:

library(ggplot2)

ggplot(mpg, aes(displ, hwy))  
  geom_point()  
  facet_wrap(vars(class), strip.position = "right")  
  theme(strip.text.y = element_text(angle = 0))