R How to Control Legend Item Ordering of ggplot2 Plot (Example Code)

In this article you’ll learn how to sort the legend items of a ggplot2 plot manually in R programming.

Setting up the Example

data(iris)                                      # Iris 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
ggplot(iris,                                    # Default legend order of ggplot2 plot
       aes(x = Sepal.Length,
           y = Sepal.Width,
           color = Species)) +
  geom_point()

r graph figure 1 r control legend item ordering ggplot2 plot

Example: Manually Specify Order of ggplot2 Legend Items

iris_new <- iris                                # Replicate iris
iris_new$Species <- factor(iris_new$Species,    # Relevel group factor
                           levels = c("virginica", "setosa", "versicolor"))
ggplot(iris_new,                                # ggplot2 plot with different legend order
       aes(x = Sepal.Length,
           y = Sepal.Width,
           color = Species)) +
  geom_point()

r graph figure 2 r control legend item ordering ggplot2 plot

Leave a Reply

Your email address will not be published.

Fill out this field
Fill out this field
Please enter a valid email address.
You need to agree with the terms to proceed

Menu
Top