• Article

Tuple<T1, T2> Class

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Represents a 2-tuple, or pair.

Inheritance Hierarchy

System.Object
  System.Tuple<T1, T2>

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

Syntax

'Declaration
Public Class Tuple(Of T1, T2) _
    Implements IStructuralEquatable, IStructuralComparable, IComparable

public class Tuple<T1, T2> : IStructuralEquatable, IStructuralComparable, 
    IComparable

Type Parameters

  • T1
    The type of the tuple's first component.
  • T2
    The type of the tuple's second component.

The Tuple<T1, T2> type exposes the following members.

Constructors

  Name Description
Public method Tuple<T1, T2> Initializes a new instance of the Tuple<T1, T2> class.

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Properties

  Name Description
Public property Item1 Gets the value of the current Tuple<T1, T2> object's first component.
Public property Item2 Gets the value of the current Tuple<T1, T2> object's second component.

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Methods

  Name Description
Public method Equals Returns a value that indicates whether the current Tuple<T1, T2> object is equal to a specified object. (Overrides Object.Equals(Object).)
Protected method Finalize Allows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
Public method GetHashCode Returns the hash code for the current Tuple<T1, T2> object. (Overrides Object.GetHashCode().)
Public method GetType Gets the Type of the current instance. (Inherited from Object.)
Protected method MemberwiseClone Creates a shallow copy of the current Object. (Inherited from Object.)
Public method ToString Returns a string that represents the value of this Tuple<T1, T2> instance. (Overrides Object.ToString().)

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Explicit Interface Implementations

  Name Description
Explicit interface implemetationPrivate method IComparable.CompareTo Compares the current Tuple<T1, T2> object to a specified object and returns an integer that indicates whether the current object is before, after, or in the same position as the specified object in the sort order.
Explicit interface implemetationPrivate method IStructuralComparable.CompareTo Compares the current Tuple<T1, T2> object to a specified object by using a specified comparer, and returns an integer that indicates whether the current object is before, after, or in the same position as the specified object in the sort order.
Explicit interface implemetationPrivate method IStructuralEquatable.Equals Returns a value that indicates whether the current Tuple<T1, T2> object is equal to a specified object based on a specified comparison method.
Explicit interface implemetationPrivate method IStructuralEquatable.GetHashCode Calculates the hash code for the current Tuple<T1, T2> object by using a specified computation method.

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Remarks

A tuple is a data structure that has a specific number and sequence of values. The Tuple<T1, T2> class represents a 2-tuple, or pair, which is a tuple that has two components. A 2-tuple is similar to a KeyValuePair<TKey, TValue> structure.

You can instantiate a Tuple<T1, T2> object by calling either the Tuple<T1, T2> constructor or the static Tuple.Create<T1, T2>(T1, T2) method. You can retrieve the values of the tuple's components by using the read-only Item1 and Item2 instance properties.

Tuples are commonly used in four different ways:

  • To represent a single set of data. For example, a tuple can represent a record in a database, and its components can represent that record's fields.

  • To provide easy access to, and manipulation of, a data set. The following example defines an array of Tuple<T1, T2> objects that contain the names of students and their corresponding test scores. It then iterates the array to calculate the mean test score.

    Module Example
   Public Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
      Dim scores() As Tuple(Of String, Nullable(Of Integer)) = _ 
                      { New Tuple(Of String, Nullable(Of Integer))("Jack", 78), _
                        New Tuple(Of String, Nullable(Of Integer))("Abbey", 92), _
                        New Tuple(Of String, Nullable(Of Integer))("Dave", 88), _
                        New Tuple(Of String, Nullable(Of Integer))("Sam", 91), _
                        New Tuple(Of String, Nullable(Of Integer))("Ed", Nothing), _
                        New Tuple(Of String, Nullable(Of Integer))("Penelope", 82), _
                        New Tuple(Of String, Nullable(Of Integer))("Linda", 99), _
                        New Tuple(Of String, Nullable(Of Integer))("Judith", 84) }
      Dim number As Integer
      Dim mean As Double = ComputeMean(scores, number)
      outputBlock.Text += String.Format("Average test score: {0:N2} (n={1})", mean, number) & vbCrLf
   End Sub

   Private Function ComputeMean(scores() As Tuple(Of String, Nullable(Of Integer)), _ 
                                ByRef n As Integer) As Double
      n = 0
      Dim sum As Integer
      For Each score In scores
         If score.Item2.HasValue Then
            n += 1
            sum += score.Item2.Value
         End If
      Next
      If n > 0 Then
         Return sum / n
      Else
         Return 0
      End If
   End Function
End Module
' The example displays the following output:
'       Average test score: 88 (n=7)

    using System;

public class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      Tuple<string, Nullable<int>>[] scores = 
                    { new Tuple<string, Nullable<int>>("Jack", 78),
                      new Tuple<string, Nullable<int>>("Abbey", 92), 
                      new Tuple<string, Nullable<int>>("Dave", 88),
                      new Tuple<string, Nullable<int>>("Sam", 91), 
                      new Tuple<string, Nullable<int>>("Ed", null),
                      new Tuple<string, Nullable<int>>("Penelope", 82),
                      new Tuple<string, Nullable<int>>("Linda", 99),
                      new Tuple<string, Nullable<int>>("Judith", 84) };
      int number;
      double mean = ComputeMean(scores, out number);
      outputBlock.Text += String.Format("Average test score: {0:N2} (n={1})", mean, number) + "\n";
   }

   private static double ComputeMean(Tuple<string, Nullable<int>>[] scores, out int n)
   {
      n = 0;
      int sum = 0;
      foreach (var score in scores)
      {
         if (score.Item2.HasValue)
         {
            n += 1;
            sum += score.Item2.Value;
         }
      }
      if (n > 0)
         return sum / (double)n;
      else
         return 0;
   }
}
// The example displays the following output:
//       Average test score: 88 (n=7)

  • To return multiple values from a method without the use of out parameters (in C#) or ByRef parameters (in Visual Basic). For example, the following example uses a Tuple<T1, T2> object to return the quotient and the remainder that result from integer division.

    Module Example
   Public Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
      Dim dividend, divisor As Integer
      Dim result As Tuple(Of Integer, Integer)

      dividend = 136945 : divisor = 178
      result = IntegerDivide(dividend, divisor)
      If result IsNot Nothing Then
         outputBlock.Text += String.Format("{0} \ {1} = {2}, remainder {3}", _
                           dividend, divisor, result.Item1, result.Item2) + vbCrLf
      Else
         outputBlock.Text += String.Format("{0} \ {1} = <Error>", dividend, divisor) & vbCrLf
      End If

      dividend = Int32.MaxValue : divisor = -2073
      result = IntegerDivide(dividend, divisor)
      If result IsNot Nothing Then
         outputBlock.Text += String.Format("{0} \ {1} = {2}, remainder {3}", _
                           dividend, divisor, result.Item1, result.Item2) + vbCrLf
      Else
         outputBlock.Text += String.Format("{0} \ {1} = <Error>", dividend, divisor) & vbCrLf
      End If
   End Sub

   Private Function IntegerDivide(ByVal dividend As Integer, ByVal divisor As Integer) As Tuple(Of Integer, Integer)
      Try
         Dim quotient As Integer = dividend \ divisor
         Dim remainder As Integer = dividend Mod divisor
         Return New Tuple(Of Integer, Integer)(quotient, remainder)
      Catch e As DivideByZeroException
         Return Nothing
      End Try
   End Function
End Module
' The example displays the following output:
'       136945 \ 178 = 769, remainder 63
'       2147483647 \ -2073 = -1035930, remainder 757

    using System;

public class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      int dividend, divisor;
      Tuple<int, int> result;

      dividend = 136945; divisor = 178;
      result = IntegerDivide(dividend, divisor);
      if (result != null)
         outputBlock.Text += String.Format(@"{0} \ {1} = {2}, remainder {3}",
                           dividend, divisor, result.Item1, result.Item2) + "\n";
      else
         outputBlock.Text += String.Format(@"{0} \ {1} = <Error>", dividend, divisor) + "\n";

      dividend = Int32.MaxValue; divisor = -2073;
      result = IntegerDivide(dividend, divisor);
      if (result != null)
         outputBlock.Text += String.Format(@"{0} \ {1} = {2}, remainder {3}",
                           dividend, divisor, result.Item1, result.Item2) + "\n";
      else
         outputBlock.Text += String.Format(@"{0} \ {1} = <Error>", dividend, divisor) + "\n";
   }

   private static Tuple<int, int> IntegerDivide(int dividend, int divisor)
   {
      try
      {
         int quotient = dividend / divisor;
         int remainder = dividend % divisor;

         return new Tuple<int, int>(quotient, remainder);
      }
      catch (DivideByZeroException)
      {
         return null;
      }
   }
}
// The example displays the following output:
//       136945 \ 178 = 769, remainder 63
//       2147483647 \ -2073 = -1035930, remainder 757

  • To pass multiple values to a method through a single parameter. For example, the Thread.Start(Object) method has a single parameter that lets you supply one value to the method that the thread executes at startup. If you supply a Tuple<T1, T2> object as the method argument, you can supply the thread’s startup routine with two items of data.

Version Information

Silverlight

Supported in: 5, 4

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.