Heatmaps
Learn how to build and customize heatmaps in ggplot2.
Introduction to heatmaps
Heatmaps are graphical representations of data where the values are represented as colors. They are a valuable tool for visualizing and understanding large datasets, as they can help identify patterns and trends in the data. In ggplot2
, heatmaps can be created using the geom_tile()
function.
Let’s first create a numerical matrix in R using the rnorm
function, as shown in the code below:
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set.seed(123)m <- matrix(rnorm(50), nrow = 5, ncol = 5)colnames(m) <- c("A", "B", "C", "D", "E")rownames(m) <- c("P", "Q", "R", "S", "T")m
- Line 1: We set the
seed
parameter as123
to reproduce the same set of random numbers every time we run the code. - Line 2: We create a matrix named
m
using thematrix()
function with rows and columns specified by the argumentsnrow=5
andncol=5
, respectively. We generate