First, I have a matrix like
1 2 3 4 1.11 2 3 4 31 2 3 5 42 3 4 1 6...
Second, what I would like to do is to summarize the matrix with the first four columns. That is, here, I want to take an average of the entries of the fifth item for the rows that has the same first four columns. In this example, it will be
1 2 3 4 2.051 2 3 5 42 3 4 1 6...
Please advise.
Best Answer