MATLAB: Output of k means clusters “idx”

clusteridxkmeans

idx = kmeans(X,k)
idx means what ? i read description of function but i still confused
how i can use it
if i need to know the output of each cluster without plot
like cluster 1(4,6,7)
cluster 2(5,7,9)

Best Answer

idx will be a vector which has as many entries as there are rows in X.
The j'th entry, idx(j) tells you the cluster number that X(j,:) belongs to.
which_in_cluster = cell(k,1);
for j = 1 : k
    which_in_cluster{j} = find(idx == j);
end
Now which_in_cluster will be a cell array in which the j'th entry is a vector indicating which rows were part of the j'th cluster.
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