FINALLY: Tuples in C#
It’s taken until .NET 4.0, but Microsoft has finally decided to add tuples to the C# language. Here are their prototypes:
/* all tuples are defined under the System namespace */
[SerializableAttribute]
public class Tuple<T1> : IStructuralEquatable,
IStructuralComparable,
IComparable
[SerializableAttribute]
public class Tuple<T1, T2> : IStructuralEquatable,
IStructuralComparable,
IComparable
[SerializableAttribute]
public class Tuple<T1, T2, T3> : IStructuralEquatable,
IStructuralComparable,
IComparable
/* and all the way up to ... */
[SerializableAttribute]
public class Tuple<T1, T2, T3, T4, T5, T6, T7, TRest> : IStructuralEquatable,
IStructuralComparable,
IComparable
It’s a bit unfortunate for those of us who’d already added our own tuple implementations to our solutions because we’d given up hoping for built-in types years ago. Better late than never though.
Tuples can be created using either the constructors for your type’s corresponding arity, or more easily using the static Tuple.Create method:
Tuple<int, string> who1 = new Tuple<int, string>(1, "Bob");
Tuple<int, string> who2 = Tuple.Create(2, "Bella");
Tuple elements are accessed using the readonly Item1, Item2, Item3, … properties:
string name1 = who1.Item2; /* "Bob" */
string id2 = who2.Item1; /* 2 */
In case you’re wondering, you can build a really big tuple using the last type arity: Tuple<T1, T2, ..., TRest>. The final TRest parameter is used to hold a second tuple inside the first one, and you could even put a third tuple inside the second and so on. As you might expect though, the syntax is clumsy:
Tuple<int, int, int, int, int, int, int, Tuple<int, int, int>> bigTuple =
Tuple.Create(
/* T1 through T7 */
1, 2, 3, 4, 5, 6, 7,
/* TRest */
Tuple.Create(8, 9, 10)
);
So, we’re not going to see anymore out parameters right guys?