C# Tuple

A tuple is a data structure that has a specific number and sequence of values, the values in a tuple can either be of the same type or even be of dissimilar types . It introduced in .NET Framework 4.0 and the System.Tuple class provides static methods to create tuple objects.

Syntax

 
Tuple <T1>(T1) //for single elements
Tuple <T1, T2>(T1, T2) //for two elements
Tuple <T1, T2, T3>(T1, T2, T3) //for three elements
.
.
.
Tuple <T1, T2, T3, T4, T5, T6, T7, Rest> //for eight elements

example

 
// Tuple with two elements
Tuple<string, int> 2Tuple = new Tuple<string, int>("John", 25);

C# Tuples allow us to Create, access, and manipulate a data set. You can add elements from 1 to 8 . If you try to add elements greater than eight, then the compiler will throw an error. Tuples allows us to represent multiple data into a single data set. It can also store duplicate elements . Moreover, it allows you to pass multiple values to a method with the help of single parameters.

The order of the elements in a Tuple is defined at the time of creation. Once we create the Tuple, we cannot change the values of its fields (immutable) . Also, the size of the Tuple is fixed since it cannot be changed once it has been defined at the time of creation.

Create() method in Tuple

You can create a Tuple < > using its constructor or the "Create()" method. The following code snippet shows how you can create and initialize a Tuple.

 
// 1 tuple using create method
var tuple1 = Tuple.Create("one");
// 2 tuple using create method
var tuple2 = Tuple.Create("one", "two");
// 4 tuple using create method
var tuple4 = Tuple.Create("one", "two", "three", "four");
// 8 tuple using create method
var tuple8 = Tuple.Create("one", "two", "three", "four" , "five" , "six", "seven", "eight");

Accessing Tuple Elements

You can access the tuple object elements with Item < positionNumber > properties. For example, the first element can be accessed like Item1, the second element can be accessed like Item2, and so on based on our requirements.

 
using System;
namespace Tuple2Example
{
  class Program
  {
    static void Main(string[] args)
    {
      //tuple for 2 elements
      var student = Tuple.Create("John", 15);
      var name = student.Item1; // John
      var age = student.Item2; // 15
      Console.WriteLine(name + "  " + age);
      Console.ReadKey();
    }
  }
}

output

 
Name : John  Age: 15

example

 
using System;
namespace Tuple8Example
{
  class Program
  {
    static void Main(string[] args)
    {
      //tuple for eight elements
      var numbers = Tuple.Create(1, 2, "three", 4, "five", 6, 7, "eight");
      var n1 = numbers.Item1; // 1
      var n2 = numbers.Item2; // 2
      var n3 = numbers.Item3; // three
      var n4 = numbers.Item4; // 4
      var n5 = numbers.Item5; // five
      var n6 = numbers.Item6; // 6
      var n7 = numbers.Item7; // 7
      var n8 = numbers.Rest; // eight
      Console.WriteLine(n1 + " " + n2 + " " + n3 + " " + n4 + " " + n5 + " " + n6 + " " + n7 + " " + n8);
      Console.ReadKey();
    }
  }
}

output

 
1 2 three 4 five 6 7 (eight)

How to iterate over a C# tuple?

Once your Tuple is created and initialized, you can iterate it much the same way you would with a collection .

 
using System;
using System.Collections;
using System.Collections.Generic;
namespace TupleForeachExample
{
  class Program
  {
    static void Main(string[] args)
    {
      var students = new List<Tuple<int, string, int>>
      {
        Tuple.Create(1, "John", 15),
        Tuple.Create(2, "Doe", 15 ),
        Tuple.Create(3, "Steve ", 15 )
      };
      foreach (Tuple<int, string, int> tuple in students)
      {
        Console.WriteLine("Roll No. : " + tuple.Item1 + "  " + "Name : " + tuple.Item2 +  "  " + "Age : " + tuple.Item3);
      }
      Console.ReadKey();
    }
  }
}

output

 
Roll No. : 1  Name : John  Age : 15
Roll No. : 2  Name : Doe  Age : 15
Roll No. : 3  Name : Steve   Age : 15

Nested Tuple

You can include the nested tuple object anywhere in the tuple sequence. However, it is recommended to place the nested tuple at the end of the sequence so that you can be accessed using the tuple Rest property .

 
using System;
namespace Tuple8Example
{
  class Program
  {
    static void Main(string[] args)
    {
      var nestedTuple = Tuple.Create(1, 2, Tuple.Create("three", "four", "five"));
      var n1= nestedTuple.Item1; // returns 1
      var n2 = nestedTuple.Item2; // returns 2
      var n3 = nestedTuple.Item3; // returns (3, 4, 5, 6, 7,  8)
      var n4 = nestedTuple.Item3.Item1; // returns 3
      var n5 = nestedTuple.Item3.Item3; // returns 3
      Console.WriteLine(n1 + " " + n2 + " " + n3 + " " + n4 + " " + n5 );
      Console.ReadKey();
    }
  }
}

output

 
1 2 (three, four, five) three five

Limitations:

The Tuple classes will cause more performance issues because they are reference types.

Next : How to use C# ArrayList Class