Set number of columns (or rows) in a facetted plot

Question

I have a facetted plot like this:

ggplot(mtcars, aes(x = hp, y = mpg)) +
  geom_point() +
  facet_grid(. ~ carb)

However, the graph is too

Answer 1

You can use the ncol (or nrow) argument in facet_wrap:

ggplot(mtcars, aes(x = hp, y = mpg)) +
 geom_point()  +
 facet_wrap(~ carb, ncol = 3)