Tuple(Of T1, T2, T3).Item1 Property

 
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Gets the value of the current Tuple(Of T1, T2, T3) object's first component.

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

Public ReadOnly Property Item1 As T1

Property Value

Type: T1

The value of the current Tuple(Of 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(Of 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(Of 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(Of T1, T2, T3) object that is returned by the ComputeStatistics method. The Item1 property contains the number of cases.

Module Example
   Public Sub Main()
      Dim 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) }
      Dim result = ComputeStatistics(scores)
      Console.WriteLine("Mean score: {0:N2} (SD={1:N2}) (n={2})", 
                        result.Item2, result.Item3, result.Item1)
   End Sub

   Private Function ComputeStatistics(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)

Universal Windows Platform
Available since 8
.NET Framework
Available since 4.0
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 4.0
Windows Phone Silverlight
Available since 8.0
Windows Phone
Available since 8.1
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