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Aggregating numbers based on first column index

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Mido
Mido 2016-11-4
评论： Mido 2016-11-5
Hi
I have a matrix as follows
x=[1 3;
1 4;
1 6;
2 5;
2 7;
3 4;
3 11;
3 1;
3 2]
I want to write a code or a loop that aggregates the numbers in the second column for each different number in the first column.
The result should be
y= [1 13;
2 12;
3 18]

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Walter Roberson
Walter Roberson 2016-11-4
[unique_keys, ~, uq_idx] = unique(x(:,1));
totaled_data = accumarray(uq_idx, x(:,2));
y = [unique_keys, totaled_data];

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