Question

I want to do what SQL’s GROUP BY does in MATLAB. For example,

M = [
1, 5;
2, 5;
3, 5;
1, 6;
2, 6;
1,7 ]

SQL: SELECT MAX(c1), c2 FROM M(c1, c2) GROUP BY 2

Result = [
3, 5;
2, 6;
1, 7]

How can I do this in Matlab?

Answer 1

grpstats in the Statistics Toolbox can do this:

>> [grpstats(M(:,1), M(:,2), {'max'}) unique(M(:,2))]

ans =

     3     5
     2     6
     1     7