Is there a way to print branch distances for hclust function?
On Sun, Dec 11, 2011 at 8:43 PM, kbrownk <kbrownk at gmail.com> wrote:
The R function hclust is used to do cluster analysis, but based on R help I see no way to print the actual fusion distances (that is, the vertical distances for each connected branch pairs seen in the cluster dendrogram). Any ideas? I'd like to use them test for significant differences from the mean fusion distance (i.e. The Best Cut Test). To perform a cluster analysis I'm using: x <- dist(mydata, method = "euclidean") # distance matrix y <- hclust(x, method="ward") #clustering (i.e. fusion) method plot(y) # display dendogram Thanks, kbrownk
You need to dig a bit deeper in the help file :) The return value is a list that contains, among others, components 'merge' and 'height'. The 'merge' component tells you which objects were merged at each particular step, and the 'height' component tells you what the merging height at that step was. The (slightly) tricky part is to relate the merge component to actual objects - AFAIK there is no function for that. The function cutree() using the argument k and varying it between 2 and n should basically do it for you but you need to match it to the entries in 'merge'. Maybe someone else knows a better way to do this. HTH, Peter