Lookup(TKey, TElement) Represents a collection of keys each mapped to one or more values. : HashSet « Data Structure « VB.Net

1. VB.Net
2. Data Structure
3. HashSet

Lookup(TKey, TElement) Represents a collection of keys each mapped to one or more values.

 


Structure Product
    Public Company As String
    Public Weight As Double
    Public TrackingNumber As Long
End Structure

Public Class Example
    Public Shared Sub Main()
    Dim packages As New System.Collections.Generic.List(Of Product)(New Product() _
        {New Product With {.Company = "A", .Weight = 25.2, .TrackingNumber = 1L}, _
          New Product With {.Company = "B", .Weight = 18.7, .TrackingNumber = 2L}, _
          New Product With {.Company = "C", .Weight = 6.0, .TrackingNumber = 3L}, _
          New Product With {.Company = "D", .Weight = 9.3, .TrackingNumber = 4L}, _
          New Product With {.Company = "E", .Weight = 33.8, .TrackingNumber = 5L}})

    Dim lookup As ILookup(Of Char, String) = packages.ToLookup(Function(ByVal p) Convert.ToChar(p.Company.Substring(0, 1)), _
                          Function(ByVal p) p.Company & " " & p.TrackingNumber)

    For Each packageGroup As IGrouping(Of Char, String) In lookup
        Console.WriteLine(packageGroup.Key)
        For Each str As String In packageGroup
            Console.WriteLine(str)
        Next
    Next
    Dim count As Integer = lookup.Count
    Dim cgroup As System.Collections.Generic.IEnumerable(Of String) = lookup("C"c)
    For Each str As String In cgroup
        Console.WriteLine(str)
    Next
    Dim hasG As Boolean = lookup.Contains("G"c)
 End Sub
End Class

   
  

Related examples in the same category