MATLAB: Using clusterdata and extracting data from it’s indexes.

arraysclusterdataindexing

Hello,
I have an array of points say A = [1,13,14,2,15,16,3,17];
I use clusterdata (with criterion as distance) which returns me the cluster number each data point in A belongs to:
T = [1,2,2,1,2,2,1,2];
I want to have a new array which separates these data points into:
B = [1,2,3] C = [13,14,15,16,17]
How do I achieve this?

Best Answer

A very simple but possibly obscure way is to use accumarray:
Asplit = accumarray(T', A, [], @(v) {v});
Note that the output is a cell array where each cell is a cluster. It's much better to use a cell array than individually named variables.
The above line is equivalent to:
Asplit = cell(max(T), 1);
for cluster = 1:max(T)
   Asplit{cluster} = A(T == cluster);
end
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