// NOTE: sets are immutable val set_numbers: Set[Int] = Set(1, 3, 5, 7, 9) // Set(5, 1, 9, 7, 3) set_numbers.contains(3) // true set_numbers.contains(2) // false // mutable set val set_mutable_one = scala.collection.mutable.Set(1, 3, 5) val set_mutable_two = scala.collection.mutable.Set(5, 7, 9) set_mutable_two += 11 // Set(9, 5, 7, 11) set_mutable_two -= 11 // Set(9, 5, 7) // set operations val A = set_mutable_one.clone val B = set_mutable_two.clone A | B // Set(9, 1, 5, 3, 7) A & B // Set(5) A &~ B // Set(1, 3) A union B // Set(9, 1, 5, 3, 7) A intersect B // Set(5) A diff B // Set(1, 3) A subsetOf B // false