R help - Feb 2012 - kmeans: how to retrieve clusters

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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On Mon, Feb 27, 2012 at 3:18 PM, ikuzar <razuki at hotmail.fr>
wrote:
> 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$cluster did not yield what I expected ...
Not sure what you mean by "process each cluster" and why kres$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)
>  kres = kmeans(m, 2)
> kres$cluster
[1] 2 2 1 1
> set.seed(1)
> kres = kmeans(m, 2)
> kres$cluster
[1] 1 1 2 2
> set.seed(200)
> kres = kmeans(m, 2)
> kres$cluster
[1] 2 2 1 1
> kres = kmeans(m, 2)
> kres$cluster
[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.

Hi, 

Ok, I understand what you mean.

I wanted to get sorted data group by cluster  in output ...
But I have to do it myself using kres$cluster

thanks for your help

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