Asymmetric expansion of ggplot axis limits

Question

How do you adjust the expansion of limits asymmetrically in ggplot? For example,

library(ggplot2)

ggplot(mtcars) + 
  geom_bar(aes(x = cyl), width = 1)
         


        

Answer 1

I have now tried to add code for this to ggplot2; see issue #1669 and the corresponding pull request. If it is accepted, the syntax for the expand argument will been changed from c(m, a) to c(m_lower, a_lower, m_uppper, a_upper), for specifying separate expansion values for the lower and upper range limits. (The old syntax will still continue to work, though, as the first two elements will be reused if elements three and/or four are missing.)

With this new syntax, you can use

ggplot(mtcars) +
  geom_bar(aes(x = cyl), width = 1) +
  scale_y_continuous(expand = c(0, 0, 0.05, 0))

The result looks like this:

It also works with facetting:

ggplot(mtcars) +
  geom_bar(aes(x = cyl, fill = factor(vs)), width = 1) +
  facet_grid(vs ~ ., scales = "free_y") +
  scale_y_continuous(expand = c(0, 0, 0.05, 0))