How can we put label of hclust in table according to clusters formed in dendogram

Question

I have a dendogram with clusters having many leaf nodes/labels How can I put these labels of hclust in a table row wise according to the clusters formed using R

Answer 1

I believe the more direct way to do it is to use cutree (and not go through rect.dendrogram):

> d1 <- USArrests[1:10,]
> d1 <- USArrests[1:10,]
> hc <- hclust(dist(d1))
> hcc <- cutree(hc, k = 3)
> hcc
    Alabama      Alaska     Arizona    Arkansas  California 
          1           1           2           1           2 
   Colorado Connecticut    Delaware     Florida     Georgia 
          1           3           1           2           1 
> data.frame(d1, hcc)
            Murder Assault UrbanPop Rape hcc
Alabama       13.2     236       58 21.2   1
Alaska        10.0     263       48 44.5   1
Arizona        8.1     294       80 31.0   2
Arkansas       8.8     190       50 19.5   1
California     9.0     276       91 40.6   2
Colorado       7.9     204       78 38.7   1
Connecticut    3.3     110       77 11.1   3
Delaware       5.9     238       72 15.8   1
Florida       15.4     335       80 31.9   2
Georgia       17.4     211       60 25.8   1

pro tip: if you're using dendrogram instead of hclut, you can use the dendextend package in order to have cutree for dendrogram as well.

Answer 2

You need to access the data stored in your rect.hclust object, along these lines:

obj <- rect.hclust(my_matrix, k = n)
str(obj)

By inspecting obj with str you will find a list of all the variables grouped by cluster. You can export these into a tabular form, for example by using lapply:

labels <- lapply(obj, paste0, collapse = ",")