# How to group numeric variables in to single index

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Kanakaiah Jakkula on 23 Dec 2016
Commented: Walter Roberson on 26 Dec 2016
Hi,
I have below table contains three variables, each row represents a single observation, and I want to group them into single index. Kindly some one help how to group them in to single index.
4.82 0.3 10056
5.23 0.9 1235
4.98 0.85 125
9.65 0.46 4568
11.23 1.2 45689
5.98 0.78 46985
4.23 0.65 41256
4.32 1.1 2356
5.3 1.2 1815
1.25 3.1 1230
6.98 5.1 252
10.23 2.3 1236
2.6 0.59 142
Walter Roberson on 23 Dec 2016
What should the grouping be? All of the values appear to be unique.
Kanakaiah Jakkula on 23 Dec 2016
Yes, all 4 variables should be combined to see as a single index. So, each row represent a single value.

Walter Roberson on 23 Dec 2016
Edited: Walter Roberson on 23 Dec 2016
A = [4.82 0.3 10056
5.23 0.9 1235
4.98 0.85 125
9.65 0.46 4568
11.23 1.2 45689
5.98 0.78 46985
4.23 0.65 41256
4.32 1.1 2356
5.3 1.2 1815
1.25 3.1 1230
6.98 5.1 252
10.23 2.3 1236
2.6 0.59 142];
A_grouped = mat2cell(A, ones(1, size(A,1)), 3);
Now A_grouped{1} will be the first row, A_grouped{2} will be the second row, and so on -- the rows would be grouped in a single index.
If this is not what you want, then you will need to show us a sample output.
Kanakaiah Jakkula on 26 Dec 2016
Yes Sir, dimention reduction in directly, but just give to give more weightage to the one which have highvariance.
Walter Roberson on 26 Dec 2016
V = var(A(:, 1:2));
output = A(:, 3) ./ sum( bsxfun( @mult, V, A(:,1:2)), 2);

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