How to do it...

Let's get started with the recipe:

1. Draw the base aesthetics under an object:

> library(ggplot2)
> base <-ggplot(car::Salaries, 
                aes(x = rank, y = salary))

1. Call geom_violin() to draw a simple violin plot:

> base + geom_violin()

Following figure is the output obtained by the preceding code:

Figure 3.9 Simple violin plot.

1. To enhance it, you can fill the inside and add a box plot:

> base + geom_violin(fill = 'steelblue1') + 
    geom_boxplot(outlier.shape = NA, width = .1)

Following figure demonstrates the result:

Figure 3.10: Violins and boxes combined

Keep going on for explanations!