HashSet(T).IsProperSubsetOf Method tells whether a HashSet(Of T) object is a proper subset of the specified collection.
Imports System Imports System.Collections.Generic Class Program Shared Sub Main() Dim lowNumbers As HashSet(Of Integer) = New HashSet(Of Integer)() Dim allNumbers As HashSet(Of Integer) = New HashSet(Of Integer)() For i As Integer = 1 To 4 lowNumbers.Add(i) Next i For i As Integer = 0 To 9 allNumbers.Add(i) Next i Console.WriteLine("lowNumbers overlaps allNumbers: {0}", lowNumbers.Overlaps(allNumbers)) Console.WriteLine("allNumbers and lowNumbers are equal sets: {0}", allNumbers.SetEquals(lowNumbers)) Console.WriteLine("lowNumbers is a subset of allNumbers: {0}", lowNumbers.IsSubsetOf(allNumbers)) Console.WriteLine("lowNumbers is a proper subset of allNumbers: {0}", lowNumbers.IsProperSubsetOf(allNumbers)) End Sub End Class