Annotate Count by Group to ggplot2 Boxplot in R (Example Code)
In this R programming post you’ll learn how to add the observations by group to a boxplot.
Preparing the Example
data(iris) # Example data head(iris) # Sepal.Length Sepal.Width Petal.Length Petal.Width Species # 1 5.1 3.5 1.4 0.2 setosa # 2 4.9 3.0 1.4 0.2 setosa # 3 4.7 3.2 1.3 0.2 setosa # 4 4.6 3.1 1.5 0.2 setosa # 5 5.0 3.6 1.4 0.2 setosa # 6 5.4 3.9 1.7 0.4 setosa |
install.packages("ggplot2") # Install ggplot2 package library("ggplot2") # Load ggplot2 package |
my_plot <- ggplot(iris, # Drawing ggplot2 boxplot without counts aes(x = Species, y = Petal.Width)) + geom_boxplot() my_plot |
Example: Annotating Count Labels by Group to ggplot2 Boxplot
my_plot + # Annotating count labels to boxplot annotate("text", x = 1:length(table(iris$Species)), y = aggregate(Petal.Width ~ Species, iris, median)[ , 2], label = paste("n =", table(iris$Species)), size = 5, col = "purple", vjust = - 0.6) |
Further Resources & Related Tutorials
Please find some related R tutorials on topics such as colors, ggplot2, and groups in the following list.