Suppose we have a data frame df that looks like:

                team_1   team_2   team_3
very_effective   3        5        8
effective        5        6        9  
ineffective      6        8        20

I want to create a heatmap that has different colour squares which are darker if the value is higher. I tried the following code but I get the error object 'X1' is not found. Does anyone know how to fix? Thanks!

library(ggplot2)
ggp <- ggplot(df, aes(X1, X2))                             # Create heatmap with ggplot2
  geom_tile()
ggp 

CodePudding user response：

aes() expects vectors for x- and y-values; not a crosstable, and also not undefined variables:

Usage
aes(x, y, ...)

source: