A basic scatter plot has a set of points plotted at the intersection of their values along x and y axes. Sometimes, we might wish to further distinguish between these points based on another value associated with the points. In this recipe, we will learn how we can group data points using colors.
To try out this recipe, start R and type the recipe in the command prompt. You can also choose to save the recipe as a script so that you can use it again later on.
We will also need the lattice
and ggplot2
packages. The lattice
package is included automatically in the base R installation, but we will need to install the ggplot2
package. To do this, run the following command in the R prompt:
install.packages("ggplot2")
As a first example, let's use the xyplot()
command of the lattice library:
library(lattice) xyplot(mpg~disp, data=mtcars, groups=cyl, auto.key=list(corner=c(1,1)))