Machine Learning with R Cookbook - Second Edition

How to do it...

Perform the following steps to cut the hierarchy of clusters into a given number of clusters:

1. First, categorize the data into four groups:

        > fit = cutree(hc, k = 4)  

2. You can then examine the cluster labels for the data:

        > fit
        Output
         [1] 1 1 2 1 2 1 2 2 1 1 1 2 2 1 1 1 2 1 2 3 4 3 4 3 3 4 4 3 4
         [30] 4 4 3 3 3 4 4 3 4 4 4 4 4 4 4 3 3 4 4 4 3 4 3 3 4 4 4 3 4
         [59] 4 3

3. Count the amount of data within each cluster:

        > table(fit)
        Output
        fit
         1  2  3  4 
        11  8 16 25

4. Finally, you can visualize how data is clustered with a red rectangle border:

        > plot(hc)
        > rect.hclust(hc, k = 4 , border="red")  

Using the red rectangle border to ...