HashSet(T).SymmetricExceptWith Method keeps elements that are present either in that object or in the specified collection, but not both.
Imports System Imports System.Collections.Generic Class Program Shared Sub Main() Dim lowNumbers As HashSet(Of Integer) = New HashSet(Of Integer)() Dim highNumbers As HashSet(Of Integer) = New HashSet(Of Integer)() For i As Integer = 0 To 5 lowNumbers.Add(i) Next i For i As Integer = 3 To 9 highNumbers.Add(i) Next i lowNumbers.SymmetricExceptWith(highNumbers) Console.Write("lowNumbers contains {0} elements: ", lowNumbers.Count) End Sub End Class