Removing Unused Factors from a Facet in ggplot2

ggplot2, r

Solution

I think all you need is `scales = "free_y"`:

p0 = ggplot(mydf, aes(x = x, y = y)) +
  geom_point() +
  facet_wrap(~ cat, ncol = 1,scales = "free_y")

p0

Problem

I am trying to figure out a neat way to remove unused factors from a facet in ggplot2. Here is a minimal example ``` # DUMMY DATA mydf = data.frame( x = rpois(6, 25), y = LETTERS[1:6], cat = c(rep('AA', 3), rep('BB', 3))) # PLOT IT! p0 = ggplot(mydf, aes(x = x, y = y)) + geom_point() + facet_wrap(~ cat, ncol = 1) ``` From the plot below, you can see that factors D, E and F are plotted in facet AA despite the fact that there is no corresponding data. What I want is for a way to eliminate {D, E, F} from facet AA and similarly {A, B, C} from facet BB. Is there a neat way to do this, or even a hack would be acceptable.

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