adamlaiacano:

When you have a factor with many levels and want to see a histogram, it’s always more useful to see them sorted in some kind of order. An example of this is shown below:

labels <- c( rep("a", 100*rexp(1)), rep("b", 100*rexp(1)), rep("c", 100*rexp(1)), rep("d", 100*rexp(1)))
x <-...