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Tuple<T1, T2, T3>.Item1 Property

Gets the value of the current Tuple<T1, T2, T3> object's first component.

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

public T1 Item1 { get; }

Property Value

Type: T1
The value of the current Tuple<T1, T2, T3> object's first component.

You can dynamically determine the type of the Item1 component in one of two ways:

  • By calling the GetType method on the value that is returned by the Item1 property.

  • By retrieving the Type object that represents the Tuple<T1, T2, T3> object, and retrieving the first element from the array that is returned by its Type.GetGenericArguments method.

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 score, standard deviation, and number of cases from which the statistics are calculated. These values are stored in the Tuple<T1, T2, T3> object that is returned by the ComputeStatistics method. The Item1 property contains the number of cases.


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)


Silverlight

Supported in: 5, 4

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

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