I need the cumlative sum of the second column of Data grouped by (or reset at each change in) the first column of Data please:
Data = [[1;1;1; 2;2;2; 3;3;3], [1;0;1; 0;1;1; 0;1;0]]Answer = [Data, [1;1;2; 0;1;2; 0;1;1]]Data = 1 1 1 0 1 1 2 0 2 1 2 1 3 0 3 1 3 0Answer = 1 1 1 1 0 1 1 1 2 2 0 0 2 1 1 2 1 2 3 0 0 3 1 1 3 0 1
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