项目
11/18/2011

Tuple<T1, T2, T3> Class

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Represents a 3-tuple, or triple.

Inheritance Hierarchy

System.Object
System.Tuple<T1, T2, T3>

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

Syntax

'Declaration
Public Class Tuple(Of T1, T2, T3) _
    Implements IStructuralEquatable, IStructuralComparable, IComparable

public class Tuple<T1, T2, T3> : IStructuralEquatable, 
    IStructuralComparable, IComparable

Type Parameters

T1
The type of the tuple's first component.

T2
The type of the tuple's second component.

T3
The type of the tuple's third component.

The Tuple<T1, T2, T3> type exposes the following members.

Constructors

	Name	Description
	Tuple<T1, T2, T3>	Initializes a new instance of the Tuple<T1, T2, T3> class.

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Properties

	Name	Description
	Item1	Gets the value of the current Tuple<T1, T2, T3> object's first component.
	Item2	Gets the value of the current Tuple<T1, T2, T3> object's second component.
	Item3	Gets the value of the current Tuple<T1, T2, T3> object's third component.

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Methods

	Name	Description
	Equals	Returns a value that indicates whether the current Tuple<T1, T2, T3> object is equal to a specified object. (Overrides Object.Equals(Object).)
	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.)
	GetHashCode	Returns the hash code for the current Tuple<T1, T2, T3> object. (Overrides Object.GetHashCode().)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	ToString	Returns a string that represents the value of this Tuple<T1, T2, T3> instance. (Overrides Object.ToString().)

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Explicit Interface Implementations

	Name	Description
	IComparable.CompareTo	Compares the current Tuple<T1, T2, T3> 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.
	IStructuralComparable.CompareTo	Compares the current Tuple<T1, T2, T3> 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.
	IStructuralEquatable.Equals	Returns a value that indicates whether the current Tuple<T1, T2, T3> object is equal to a specified object based on a specified comparison method.
	IStructuralEquatable.GetHashCode	Calculates the hash code for the current Tuple<T1, T2, T3> 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, T3> class represents a 3-tuple, or triple, which is a tuple that has three components.

You can instantiate a Tuple<T1, T2, T3> object by calling either the Tuple<T1, T2, T3> constructor or the static Tuple.Create<T1, T2, T3>(T1, T2, T3) method. You can retrieve the values of the tuple's components by using the read-only Item1, Item2, and Item3 instance properties.

Tuples are commonly used in four different ways:

To represent a single set of data. For example, a tuple can represent a database record, and its components can represent individual fields of the record.

To provide easy access to, and manipulation of, a data set. The following example defines an array of Tuple<T1, T2, T3> objects that contain the names of students, their average test scores, and the number of tests taken. The array is passed to the ComputeStatistics method, which calculates the mean and standard deviation of the test scores.

Module Example
   Public Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
      Dim scores() As Tuple(Of String, Double, Integer) = _
                      { Tuple.Create("Jack", 78.8, 8), _
                        Tuple.Create("Abbey", 92.1, 9), _
                        Tuple.Create("Dave", 88.3, 9), _
                        Tuple.Create("Sam", 91.7, 8), _
                        Tuple.Create("Ed", 71.2, 5), _
                        Tuple.Create("Penelope", 82.9, 8), _
                        Tuple.Create("Linda", 99.0, 9), _
                        Tuple.Create("Judith", 84.3, 9) }
      Dim result = ComputeStatistics(scores)
      outputBlock.Text += String.Format("Mean score: {0:N2} (SD={1:N2}) (n={2})", _ 
                        result.Item2, result.Item3, result.Item1) + vbCrLf
   End Sub

   Private Function ComputeStatistics(ByVal scores() As Tuple(Of String, Double, Integer)) _
                                As Tuple(Of Integer, Double, Double)
      Dim n As Integer = 0
      Dim sum As Double = 0

      ' Compute the mean.
      For Each score In scores
         n += score.Item3
         sum += score.Item2 * score.Item3
      Next
      Dim mean As Double = sum / n

      ' Compute the standard deviation.
      Dim ss As Double = 0
      For Each score In scores
         ss = Math.Pow(score.Item2 - mean, 2)
      Next
      Dim sd As Double = Math.Sqrt(ss / scores.Length)
      Return Tuple.Create(scores.Length, mean, sd)
   End Function
End Module
' The example displays the following output:
'       Mean score: 87.02 (SD=0.96) (n=8)

using System;

public class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      Tuple<string, double, int>[] scores = 
                    { Tuple.Create("Jack", 78.8, 8),
                      Tuple.Create("Abbey", 92.1, 9), 
                      Tuple.Create("Dave", 88.3, 9),
                      Tuple.Create("Sam", 91.7, 8), 
                      Tuple.Create("Ed", 71.2, 5),
                      Tuple.Create("Penelope", 82.9, 8),
                      Tuple.Create("Linda", 99.0, 9),
                      Tuple.Create("Judith", 84.3, 9) };
      var result = ComputeStatistics(scores);
      outputBlock.Text += String.Format("Mean score: {0:N2} (SD={1:N2}) (n={2})",
                        result.Item2, result.Item3, result.Item1) + "\n";
   }

   private static Tuple<int, double, double> ComputeStatistics(Tuple<string, double, int>[] scores)
   {
      int n = 0;
      double sum = 0;

      // Compute the mean.
      foreach (var score in scores)
      {
         n += score.Item3;
         sum += score.Item2 * score.Item3;
      }
      double mean = sum / n;

      // Compute the standard deviation.
      double ss = 0;
      foreach (var score in scores)
      {
         ss = Math.Pow(score.Item2 - mean, 2);
      }
      double sd = Math.Sqrt(ss / scores.Length);
      return Tuple.Create(scores.Length, mean, sd);
   }
}
// The example displays the following output:
//       Mean score: 87.02 (SD=0.96) (n=8)

To return multiple values from a method without the use of out parameters (in C#) or ByRef parameters (in Visual Basic). For example, the previous example returns its summary test score statistics in a Tuple<T1, T2, T3> object.
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, T3> object as the method argument, you can supply the thread’s startup routine with three 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.

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