Tuple(Of T1, T2, T3, T4, T5, T6, T7, TRest).Rest Property

 
System_CAPS_noteNote

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Gets the current Tuple(Of T1, T2, T3, T4, T5, T6, T7, TRest) object's remaining components.

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

Public ReadOnly Property Rest As TRest

Property Value

Type: TRest

The value of the current Tuple(Of T1, T2, T3, T4, T5, T6, T7, TRest) object's remaining components.

The Rest property returns a nested Tuple object that allows access to the eighth though nth components of the tuple. Depending on the total number of components in the tuple, the values of the eighth through fourteenth components can be retrieved from the nested Tuple object's Item1 through Item7 properties. You can then use the Rest property of a nested Tuple(Of T1, T2, T3, T4, T5, T6, T7, TRest) object to retrieve the Tuple object at the next level of nesting.

You can dynamically determine the number of components in a nested Tuple object that is returned by the Rest property by extracting the digit from its type name. The following example provides an illustration.

Imports System.Reflection

Module Example
    Sub Main()
        Dim from1980 As Tuple(Of Integer, Integer, Integer) =
            Tuple.Create(1203339, 1027974, 951270)
        Dim from1910 As New Tuple(Of Integer, Integer, Integer, Integer, Integer, Integer, Integer, _
            Tuple(Of Integer, Integer, Integer)) _
            (465766, 993078, 1568622, 1623452, 1849568, 1670144, 1511462, from1980)
        Dim population As New Tuple(Of String, Integer, Integer, Integer, Integer, Integer, Integer, _ 
            Tuple(Of Integer, Integer, Integer, Integer, Integer, Integer, Integer, Tuple(Of Integer, Integer, Integer))) _
            ("Detroit", 1860, 45619, 79577, 116340, 205876, 285704, from1910)

        ShowComponentCount(population)
   End Sub

   Private Sub ShowComponentCount(tuple As Object) 
      Static ctr As Integer = 0
      Static totalComponents As Integer = 0
      Dim components As Integer = 0

      ctr += 1
      Dim name As String = tuple.GetType().Name
      components += Int32.Parse(name.Substring(name.IndexOf("`") + 1))
      If components = 8 Then
         totalComponents += 7
         Console.WriteLine("The tuple at level {0} has 7 components.", ctr)
         ShowComponentCount(tuple.Rest)
      Else
         totalComponents += components
         Console.WriteLine("The tuple at level {0} has {1} components.", 
                           ctr, components)
         Console.WriteLine("Total components in tuple: {0}", totalComponents)
      End If      
   End Sub        
End Module
' The example displays the following output:
'       The tuple at level 1 has 7 components.
'       The tuple at level 2 has 7 components.
'       The tuple at level 3 has 3 components.
'       Total components in tuple: 17

The following example creates a 17-tuple object that contains population data for the city of Detroit, Michigan, from 1860 to 2000. The seventh component of the 17-tuple is the population in 1900. The example uses the Rest property to retrieve the values of the eighth through fourteenth components, and it uses the Rest property of the nested Tuple(Of T1, T2, T3, T4, T5, T6, T7, TRest) object to retrieve the values of the remaining components.

Module Example
    Sub Main()
        Dim from1980 As Tuple(Of Integer, Integer, Integer) =
            Tuple.Create(1203339, 1027974, 951270)
        Dim from1910 As New Tuple(Of Integer, Integer, Integer, Integer, Integer, Integer, Integer, _
            Tuple(Of Integer, Integer, Integer)) _
            (465766, 993078, 1568622, 1623452, 1849568, 1670144, 1511462, from1980)
        Dim population As New Tuple(Of String, Integer, Integer, Integer, Integer, Integer, Integer, _ 
            Tuple(Of Integer, Integer, Integer, Integer, Integer, Integer, Integer, Tuple(Of Integer, Integer, Integer))) _
            ("Detroit", 1860, 45619, 79577, 116340, 205876, 285704, from1910)

        Console.WriteLine("Population of {0}", population.Item1)
        Console.WriteLine()
        Console.WriteLine("{0,5}  {1,14}  {2,10}", "Year", "Population", "Change")

        Dim year As Integer = population.Item2
        ShowPopulation(year, population.Item3)
        year += 10
        ShowPopulationChange(year, population.Item4, population.Item3)
        year += 10
        ShowPopulationChange(year, population.Item5, population.Item4)
        year += 10
        ShowPopulationChange(year, population.Item6, population.Item5)
        year += 10
        ShowPopulationChange(year, population.Item7, population.Item6)
        year += 10
        ShowPopulationChange(year, population.Rest.Item1, population.Item7)
        year += 10
        ShowPopulationChange(year, population.Rest.Item2, population.Rest.Item1)
        year += 10
        ShowPopulationChange(year, population.Rest.Item3, population.Rest.Item2)
        year += 10
        ShowPopulationChange(year, population.Rest.Item4, population.Rest.Item3)
        year += 10
        ShowPopulationChange(year, population.Rest.Item5, population.Rest.Item4)
        year += 10
        ShowPopulationChange(year, population.Rest.Item6, population.Rest.Item5)
        year += 10
        ShowPopulationChange(year, population.Rest.Item7, population.Rest.Item6)
        year += 10
        ShowPopulationChange(year, population.Rest.Rest.Item1, population.Rest.Item7)
        year += 10
        ShowPopulationChange(year, population.Rest.Rest.Item2, population.Rest.Rest.Item1)
        year += 10
        ShowPopulationChange(year, population.Rest.Rest.Item3, population.Rest.Rest.Item2)
    End Sub

    Private Sub ShowPopulationChange(ByVal year As Integer, ByVal newPopulation As Integer, ByVal oldPopulation As Integer)
        Console.WriteLine("{0,5}  {1,14:N0}  {2,10:P2}", year, newPopulation,
                          (newPopulation - oldPopulation) / oldPopulation / 10)
    End Sub

    Private Sub ShowPopulation(ByVal year As Integer, ByVal newPopulation As Integer)
        Console.WriteLine("{0,5}  {1,14:N0}  {2,10:P2}", year, newPopulation, "n/a")
    End Sub
End Module
' The example displays the following output:
'
'    Population of Detroit
'    Year      Population      Change
'    1860          45,619         n/a
'    1870          79,577      7.44 %
'    1880         116,340      4.62 %
'    1890         205,876      7.70 %
'    1900         285,704      3.88 %
'    1910         465,766      6.30 %
'    1920         993,078     11.32 %
'    1930       1,568,622      5.80 %
'    1940       1,623,452      0.35 %
'    1950       1,849,568      1.39 %
'    1960       1,670,144     -0.97 %
'    1970       1,511,462     -0.95 %
'    1980       1,203,339     -2.04 %
'    1990       1,027,974     -1.46 %
'    2000         951,270     -0.75 %

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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