A Tuple is a data structure, and it is useful to store the sequence of elements of different data types. Using a tuple, we can return more than one value from the methods as a single set of data.
Tuples were introduced in .NET Framework 4.0.
It can be used where you want to have a data structure to hold an object with properties, but you don’t want to create a separate type for it.
tuples are useful in the following scenarios.
- To represent or return different data type elements as a single set of data.
- To return multiple values from methods without using ref or out parameters.
- To pass multiple values to a method with a single parameter.
- Temporarily hold multiple values without creating a class or struct.
Here is the syntax for a tuple
Tuple <T1, T2, T3, T4, T5, T6, T7, TRest>
Tuple creation
We can create a Tuple<> using its constructor or the “Create” method
using System;
public class Program
{
public static void Main()
{
// Create a 3-tuple
var footballer = new Tuple<string, string, int>("Lionel Messi", "Barcelona", 2021);
// Display author info
System.Console.WriteLine("{0} signed his new contract with {1} in {2}.", footballer.Item1, footballer.Item2, footballer.Item3);
Console.WriteLine("Press Enter Key to Exit..");
Console.ReadLine();
}
}
The next code snippet creates a tuple using the static “Create” method.
using System;
public class Program
{
public static void Main()
{
// Create a 3-tuple
var footballer = Tuple.Create("Lionel Messi", "Barcelona", 2021);
// Display author info
System.Console.WriteLine("{0} signed his new contract with {1} in {2}.", footballer.Item1, footballer.Item2, footballer.Item3);
Console.WriteLine("Press Enter Key to Exit..");
Console.ReadLine();
}
}
You will see the following
Lionel Messi signed his new contract with Barcelona in 2021. Press Enter Key to Exit..
Access Elements
we can access the tuple object elements with Item<positionNumber> properties.
using System;
public class Program
{
public static void Main()
{
// Create a 3-tuple
var numbers = Tuple.Create(1, 2, 3, 4, 5, 6, 7, 8);
var item1 = numbers.Item3; // 3
var item2 = numbers.Item4; // 4
var item3 = numbers.Rest; // (8)
var item4 = numbers.Rest.Item1; // 8
System.Console.WriteLine(item1);
System.Console.WriteLine(item2);
System.Console.WriteLine(item3);
System.Console.WriteLine(item4);
Console.WriteLine("Press Enter Key to Exit..");
Console.ReadLine();
}
}
You will see this
3 4 (8) 8 Press Enter Key to Exit..
Nested Tuples
A Tuple will directly support only 8 elements. If we want to store more than 8 elements, then we need to use nested tuples.
using System;
public class Program
{
public static void Main()
{
var numbers = Tuple.Create(1, 2, 3, 4, 5, 6, 7, Tuple.Create(8, 9, 10, 11, 12));
Console.WriteLine("*****Numbers*****");
Console.WriteLine("{0}", numbers.Item2);
Console.WriteLine("{0}", numbers.Item5);
Console.WriteLine("{0}", numbers.Rest.Item1);
Console.WriteLine("{0}", numbers.Rest.Item1.Item2);
Console.WriteLine("{0}", numbers.Rest.Item1.Item3);
Console.ReadLine();
}
}
Return Type
A Tuple can be returned from a method.
using System;
public class Program
{
public static void Main()
{
var person = Footballer();
Console.WriteLine(person);
}
static Tuple<int, string, string> Footballer()
{
return Tuple.Create(1, "Lionel", "messi");
}
}
Tuple as a Method Parameter
A method can have a tuple as a parameter.
Note
The Tuple is a reference type and not a value type. It allocates on heap and could result in CPU intensive operations.
The Tuple is limited to include eight elements. You need to use nested tuples if you need to store more elements.
The Tuple elements can be accessed using properties with a name pattern Item<elementNumber>, which does not make sense.