Replace Numbers of Continuous ggplot2 Legend by Text in R (Example Code)

set.seed(289367)                                   # Example data
my_df <- data.frame(expand.grid(x = 0:5, y = 0:5),
                   z = rnorm(36))
head(my_df)
#   x y           z
# 1 0 0 -1.75255286
# 2 1 0 -0.22511947
# 3 2 0  1.00520336
# 4 3 0  1.23412700
# 5 4 0 -0.05995937
# 6 5 0 -1.11686047

set.seed(289367) # Example data my_df <- data.frame(expand.grid(x = 0:5, y = 0:5), z = rnorm(36)) head(my_df) # x y z # 1 0 0 -1.75255286 # 2 1 0 -0.22511947 # 3 2 0 1.00520336 # 4 3 0 1.23412700 # 5 4 0 -0.05995937 # 6 5 0 -1.11686047

install.packages("ggplot2")                        # Install ggplot2 package
library("ggplot2")                                 # Load ggplot2

install.packages("ggplot2") # Install ggplot2 package library("ggplot2") # Load ggplot2

my_plot <- ggplot(my_df, aes(x, y, fill = z)) +    # ggplot2 plot with default legend
  geom_tile()
my_plot

my_plot <- ggplot(my_df, aes(x, y, fill = z)) + # ggplot2 plot with default legend geom_tile() my_plot

my_plot +                                          # Change numbers in ggplot2 legend
  scale_fill_gradientn(colors = 1:10,
                       breaks = c(min(my_df$z), mean(my_df$z), max(my_df$z)),
                       labels = c("Lowest", "Middle", "Highest"))

my_plot + # Change numbers in ggplot2 legend scale_fill_gradientn(colors = 1:10, breaks = c(min(my_df$z), mean(my_df$z), max(my_df$z)), labels = c("Lowest", "Middle", "Highest"))