Determines whether a HashSet<(Of <(T>)>) object is a proper subset of the specified collection.
(in System.Core.dll)
Visual Basic (Declaration)
Public Function IsProperSubsetOf ( _
other As IEnumerable(Of T) _
) As Boolean
Dim instance As HashSet
Dim other As IEnumerable(Of T)
Dim returnValue As Boolean
returnValue = instance.IsProperSubsetOf(other)
public bool IsProperSubsetOf(
IEnumerable<T> other
)
public:
bool IsProperSubsetOf(
IEnumerable<T>^ other
)
public function IsProperSubsetOf(
other : IEnumerable<T>
) : boolean
| Exception | Condition |
|---|
| ArgumentNullException |
other is nullNothingnullptra null reference (Nothing in Visual Basic). |
An empty set is a proper subset of any other collection. Therefore, this method returns true if the collection represented by the current HashSet<(Of <(T>)>) object is empty unless the other parameter is also an empty set.
This method always returns false if Count is greater than or equal to the number of elements in other.
If the collection represented by other is a HashSet<(Of <(T>)>) collection with the same equality comparer as the current HashSet<(Of <(T>)>) object, then this method is an O(n) operation. Otherwise, this method is an O(n + m) operation, where n is Count and m is the number of elements in other.
The following example creates two disparate HashSet<(Of <(T>)>) objects and compares them to each other. In this example, lowNumbers is both a subset and a proper subset of allNumbers until allNumbers is modified, using the IntersectWith method, to contain only values that are present in both sets. Once allNumbers and lowNumbers are identical, lowNumbers is still a subset of allNumbers but is no longer a proper subset.
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.Write("lowNumbers contains {0} elements: ", lowNumbers.Count)
DisplaySet(lowNumbers)
Console.Write("allNumbers contains {0} elements: ", allNumbers.Count)
DisplaySet(allNumbers)
Console.WriteLine("lowNumbers overlaps allNumbers: {0}", _
lowNumbers.Overlaps(allNumbers))
Console.WriteLine("allNumbers and lowNumbers are equal sets: {0}", _
allNumbers.SetEquals(lowNumbers))
' Show the results of sub/superset testing
Console.WriteLine("lowNumbers is a subset of allNumbers: {0}", _
lowNumbers.IsSubsetOf(allNumbers))
Console.WriteLine("allNumbers is a superset of lowNumbers: {0}", _
allNumbers.IsSupersetOf(lowNumbers))
Console.WriteLine("lowNumbers is a proper subset of allNumbers: {0}", _
lowNumbers.IsProperSubsetOf(allNumbers))
Console.WriteLine("allNumbers is a proper superset of lowNumbers: {0}", _
allNumbers.IsProperSupersetOf(lowNumbers))
' Modify allNumbers to remove numbers that are not in lowNumbers.
allNumbers.IntersectWith(lowNumbers)
Console.Write("allNumbers contains {0} elements: ", allNumbers.Count)
DisplaySet(allNumbers)
Console.WriteLine("allNumbers and lowNumbers are equal sets: {0}", _
allNumbers.SetEquals(lowNumbers))
' Show the results of sub/superset testing with the modified set.
Console.WriteLine("lowNumbers is a subset of allNumbers: {0}", _
lowNumbers.IsSubsetOf(allNumbers))
Console.WriteLine("allNumbers is a superset of lowNumbers: {0}", _
allNumbers.IsSupersetOf(lowNumbers))
Console.WriteLine("lowNumbers is a proper subset of allNumbers: {0}", _
lowNumbers.IsProperSubsetOf(allNumbers))
Console.WriteLine("allNumbers is a proper superset of lowNumbers: {0}", _
allNumbers.IsProperSupersetOf(lowNumbers))
End Sub
' This code example produces output similar to the following:
' lowNumbers contains 4 elements: { 1 2 3 4 }
' allNumbers contains 10 elements: { 0 1 2 3 4 5 6 7 8 9 }
' lowNumbers overlaps allNumbers: True
' allNumbers and lowNumbers are equal sets: False
' lowNumbers is a subset of allNumbers: True
' allNumbers is a superset of lowNumbers: True
' lowNumbers is a proper subset of allNumbers: True
' allNumbers is a proper superset of lowNumbers: True
' allNumbers contains 4 elements: { 1 2 3 4 }
' allNumbers and lowNumbers are equal sets: True
' lowNumbers is a subset of allNumbers: True
' allNumbers is a superset of lowNumbers: True
' lowNumbers is a proper subset of allNumbers: False
' allNumbers is a proper superset of lowNumbers: False
static void Main()
{
HashSet<int> lowNumbers = new HashSet<int>();
HashSet<int> allNumbers = new HashSet<int>();
for (int i = 1; i < 5; i++)
{
lowNumbers.Add(i);
}
for (int i = 0; i < 10; i++)
{
allNumbers.Add(i);
}
Console.Write("lowNumbers contains {0} elements: ", lowNumbers.Count);
DisplaySet(lowNumbers);
Console.Write("allNumbers contains {0} elements: ", allNumbers.Count);
DisplaySet(allNumbers);
Console.WriteLine("lowNumbers overlaps allNumbers: {0}",
lowNumbers.Overlaps(allNumbers));
Console.WriteLine("allNumbers and lowNumbers are equal sets: {0}",
allNumbers.SetEquals(lowNumbers));
// Show the results of sub/superset testing
Console.WriteLine("lowNumbers is a subset of allNumbers: {0}",
lowNumbers.IsSubsetOf(allNumbers));
Console.WriteLine("allNumbers is a superset of lowNumbers: {0}",
allNumbers.IsSupersetOf(lowNumbers));
Console.WriteLine("lowNumbers is a proper subset of allNumbers: {0}",
lowNumbers.IsProperSubsetOf(allNumbers));
Console.WriteLine("allNumbers is a proper superset of lowNumbers: {0}",
allNumbers.IsProperSupersetOf(lowNumbers));
// Modify allNumbers to remove numbers that are not in lowNumbers.
allNumbers.IntersectWith(lowNumbers);
Console.Write("allNumbers contains {0} elements: ", allNumbers.Count);
DisplaySet(allNumbers);
Console.WriteLine("allNumbers and lowNumbers are equal sets: {0}",
allNumbers.SetEquals(lowNumbers));
// Show the results of sub/superset testing with the modified set.
Console.WriteLine("lowNumbers is a subset of allNumbers: {0}",
lowNumbers.IsSubsetOf(allNumbers));
Console.WriteLine("allNumbers is a superset of lowNumbers: {0}",
allNumbers.IsSupersetOf(lowNumbers));
Console.WriteLine("lowNumbers is a proper subset of allNumbers: {0}",
lowNumbers.IsProperSubsetOf(allNumbers));
Console.WriteLine("allNumbers is a proper superset of lowNumbers: {0}",
allNumbers.IsProperSupersetOf(lowNumbers));
}
/* This code example produces output similar to the following:
* lowNumbers contains 4 elements: { 1 2 3 4 }
* allNumbers contains 10 elements: { 0 1 2 3 4 5 6 7 8 9 }
* lowNumbers overlaps allNumbers: True
* allNumbers and lowNumbers are equal sets: False
* lowNumbers is a subset of allNumbers: True
* allNumbers is a superset of lowNumbers: True
* lowNumbers is a proper subset of allNumbers: True
* allNumbers is a proper superset of lowNumbers: True
* allNumbers contains 4 elements: { 1 2 3 4 }
* allNumbers and lowNumbers are equal sets: True
* lowNumbers is a subset of allNumbers: True
* allNumbers is a superset of lowNumbers: True
* lowNumbers is a proper subset of allNumbers: False
* allNumbers is a proper superset of lowNumbers: False
*/
Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
.NET Framework
Supported in: 3.5
Reference