MATLAB: Is there a function that performs similar to ‘accumarry’ but multiplies instead of accumulates

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Hello all, Is there a function that performs similar to 'accumarry' but multiplies instead of accumulates? Thank you!

Best Answer

You can multiply with accumarray if you specify the prod function as the function you want it to use. This is an adaptation of a recent Answer that wanted to take the mean of values in the second column of the matrix that shared the same value of the first column, so I originally used the mean function. Here, I’m multiplying them instead, using the prod function:
ExCellArray = {[1 3.1; 2 4.5; 3 5.7; 4 8.2; 4 5.2]};
ExArray = cell2mat(ExCellArray);
[UExA, ia, ic] = unique(ExArray(:,1));
Out = [ExArray(ia,1) accumarray(ic, ExArray(:,2), [], @prod)]
Out =
            1          3.1
            2          4.5
            3          5.7
            4        42.64
The accumarray function can do a lot of neat stuff if you just ask it nicely!
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