Tuple<T1, T2, T3> Class

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.

  C#

  VB

  Copy

  
  using System;
  
  public class Example
  {
     public static void Main()
     {
        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);
        Console.WriteLine("Mean score: {0:N2} (SD={1:N2}) (n={2})", 
                          result.Item2, result.Item3, result.Item1);
     }
  
     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.

.NET Framework

.NET Framework Client Profile

Portable Class Library

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference