Colouring plot by factor in R

Question

I am making a scatter plot of two variables and would like to colour the points by a factor variable. Here is some reproducible code:

data <- iris
plot(da         


        

Answer 1

The lattice library is another good option. Here I've added a legend on the right side and jittered the points because some of them overlapped.

xyplot(Sepal.Width ~ Sepal.Length, group=Species, data=iris, 
       auto.key=list(space="right"), 
       jitter.x=TRUE, jitter.y=TRUE)