Get Fitted Values of Regression Line from ggplot2 Plot in R (Example Code)

In this tutorial you’ll learn how to get the line fit coordinates of a ggplot2 plot regression line in the R programming language.

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,                                  # ggplot2 graphic with regression line
                  aes(x = Petal.Length,
                      y = Petal.Width)) +
  geom_point() +
  stat_smooth()
my_plot

r graph figure 1 get fitted values regression line from ggplot2 r

Example: Apply ggplot_build() Function to Get Line Fit of ggplot2 Plot Object

my_plot_data <- ggplot_build(my_plot)$data[[2]][ , 1:2]  # Extract coordinates of regression line
head(my_plot_data)
#          x          y
# 1 1.000000 0.09901847
# 2 1.074684 0.12224953
# 3 1.149367 0.14558026
# 4 1.224051 0.16937599
# 5 1.298734 0.19400205
# 6 1.373418 0.21918890

Further Resources & Related Articles

You may find some further R programming tutorials in the following list.

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