The hclust() function implements hierarchical clustering in R. In the following example we use the data from K-means Clustering 1¹ to plot the hierarchical clustering dendrogram using complete, single, and average linkage clustering, with Euclidean distance as the dissimilarity measure. We begin by clustering observations using complete linkage. The dist() function is used to compute the 50 × 50 inter-observation Euclidean distance matrix.

hc.complete <- hclust(dist(x), method = "complete")

We could just as easily perform hierarchical clustering with average or single linkage instead by setting the method argument to average or single.

Try performing hierarchical clustering with average and single linkage. Store the results in hc.average and hc.single respectively.