Quickly Exploring Data - R Graphics - page 16

Figure 2-9. Left: histogram with qplot() from ggplot2, with default bin width; right: with wider bins
If the vector is in a data frame, you can use the following syntax:
library(ggplot2)
qplot(mpg, data = mtcars, binwidth = 4 )
# This is equivalent to:
ggplot(mtcars, aes(x = mpg)) + geom_histogram(binwidth = 4 )
See Also
For more in-depth information about creating histograms, see Recipes and .
Creating a Box Plot
Problem
You want to create a box plot for comparing distributions.
Solution
To make a box plot ( Figure 2-10 ), use plot() and pass it a factor of xvalues and a vector of
yvalues. When xis a factor (as opposed to a numeric vector), it will automatically create a box
plot:
plot(ToothGrowth$supp, ToothGrowth$len)