Hi, I understand that the < operator is defined for tuples, but I'd like some kind of functor that can sort tuples in a different order; for example, the second, third, then first element of the tuple. Does boost already have something that does this? I was thinking something like this: template<uint First, uint Second, uint Third> struct SortTuple { template<typename Tuple> bool operator()(const Tuple& tup1, const Tuple& tup2) const { if (tuples::get<First>(tup1) != tuples::get<First>(tup2)) return tuples::get<First>(tup1) < tuples::get<First>(tup2); if (tuples::get<Second>(tup1) != tuples::get<Second>(tup2)) return tuples::get<Second>(tup1) < tuples::get<Second>(tup2); if (tuples::get<Third>(tup1) != tuples::get<Third>(tup2)) return tuples::get<Third>(tup1) < tuples::get<Third>(tup2); } }; typedef boost::tuple<int, int, int> MyTuple; vector<MyTuple> v; sort(v.begin(), v.end(), SortTuple<1, 2, 0>()); This was quite easy to implement, but what about an arbitrary number of tuple elements? Does this or something else with the equivalent functionality exist in boost? Cheers, Stathi