Solutions: https://www.paulamoraga.com/book-r/99-problems-ggplot2-axes-solutions.html

Dataset mtcars {datasets} contains data on fuel consumption and 10 aspects of automobile design and performance for 32 automobiles

  • mpg Miles/(US) gallon
  • disp Displacement (cu.in.)

Default plot

library(ggplot2)

ggplot(mtcars) +
  geom_point(aes(disp, mpg)) +
  scale_x_continuous(name = "Displacement")

Changing axis limits

Changing axis ticks

The breaks argument is used to specify where the ticks appear. It takes a numeric vector equal to the length of the number of ticks.

Changing tick labels

You can change the tick labels using the labels argument. In the below example, we use words instead of numbers. When adding labels, we need to ensure that the length of the breaks and labels are the same.

Changing position of labels

Y-axis example

Everything above using scale_x_continuous() can be used in the same way for y axis with scale_y_continuous().

Discrete axis labels

ggplot(mtcars) +
  geom_bar(aes(factor(cyl))) +
  scale_x_discrete(labels = c("4" = "Four", "6" = "Six", "8" = "Eight"))