Assume that you want to create a scatter plot and to add a color based on the class and finally to add a label/legend to the chart showing the mapping of the colors and classes. Let’s see how we can do it with the base package.
plot(iris$Sepal.Length, iris$Sepal.Width, col=iris$Species, main="Scatter Plot" , xlab="Sepal.Length", ylab="Sepal.Width") legend(x="topright", legend=levels(iris$Species), col=unique(as.numeric((iris$Species))), pch=1)
