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kmeans: how to retrieve clusters

4 messages · ikuzar, Peter Langfelder, R. Michael Weylandt

Original
ikuzar
# 
Hello,

I'd like to classify data with kmeans algorithm. In my case, I should get  2
clusters in output. Here is my data

colCandInd	 colCandMed
1	82	          2950.5	
2	83	         1831.5
3	1192	 2899.0	
4	1193	 2103.5

The first cluster is the two first lines
the 2nd cluster is the two last lines

Here is the code:
x = colCandList$colCandInd
y = colCandList$colCandMed
m = matrix(c(x, y), nrow = length(colCandList$colCandInd), ncol=2)
kres = kmeans(m, 2)

Is there a way to retrieve both clusters in output of the algorithm in order
to process in each cluster ? (I am looking for smthing like kres$clustList
... where I can process each cluster)

kres$cluster did not yield what I expected ...

thanks for your help


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Peter Langfelder
#
On Mon, Feb 27, 2012 at 3:18 PM, ikuzar <razuki at hotmail.fr> wrote:
Not sure what you mean by "process each cluster" and why kres$cluster
is not what you expected. kres$cluster will tell you which cluster
each point (row of your matrix) belongs to. The result depends on how
you initialize the kmeans since the inter-point distances are quite
similar to one another. For example, I get

 > set.seed(10)
[1] 2 2 1 1
[1] 1 1 2 2
[1] 2 2 1 1
[1] 1 2 1 2

So 3 times out of 4 I get the result you expect, and once a different one.

If you need the result in a different format, that should be no problem.
R. Michael Weylandt
# 
But it won't be hard at all....you can likely get what you need using
the tapply() function (or ave)

Michael
On Tue, Feb 28, 2012 at 4:33 AM, ikuzar <razuki at hotmail.fr> wrote: