Create Heatmap-Like Plot of Categorical Data in R (Example Code)

In this R programming tutorial you’ll learn how to create a heatmap-like graphic of categorical data.

Creation of Exemplifying Data

set.seed(58323214)                                         # Set random seed
df <- data.frame(obs = rep(paste0("Obs", 1:5), each = 7),  # Constructing example data frame
                 var = paste0("var", 1:7),
                 val = sample(LETTERS[1:10], 5 * 7, replace = TRUE))
df
#     obs  var val
# 1  Obs1 var1   F
# 2  Obs1 var2   I
# 3  Obs1 var3   F
# 4  Obs1 var4   C
# 5  Obs1 var5   C
# 6  Obs1 var6   F
# 7  Obs1 var7   B
# 8  Obs2 var1   D
# 9  Obs2 var2   E
# 10 Obs2 var3   D
# 11 Obs2 var4   H
# 12 Obs2 var5   D
# 13 Obs2 var6   J
# 14 Obs2 var7   C
# 15 Obs3 var1   F
# 16 Obs3 var2   E
# 17 Obs3 var3   I
# 18 Obs3 var4   H
# 19 Obs3 var5   J
# 20 Obs3 var6   C
# 21 Obs3 var7   A
# 22 Obs4 var1   F
# 23 Obs4 var2   G
# 24 Obs4 var3   E
# 25 Obs4 var4   A
# 26 Obs4 var5   C
# 27 Obs4 var6   A
# 28 Obs4 var7   I
# 29 Obs5 var1   J
# 30 Obs5 var2   A
# 31 Obs5 var3   F
# 32 Obs5 var4   E
# 33 Obs5 var5   F
# 34 Obs5 var6   A
# 35 Obs5 var7   E

Example: Drawing a Similar Plot to a Heatmap Using geom_tile() of ggplot2 Package

install.packages("ggplot2")                                # Install & load ggplot2
library("ggplot2")
ggplot(df,                                                 # Creating a heatmap-like graphic
       aes(var,
           obs,
           fill = val)) +
  geom_tile(col = "white")

r graph figure 1 create heatmap like categorical data r

Related Tutorials

Below, you may find some additional resources that are related to the topic of this page:

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