HashSet(Of T).Contains Method (T)
.NET Framework (current version)
Determines whether a HashSet(Of T) object contains the specified element.
Assembly: System.Core (in System.Core.dll)
Parameters
- item
-
Type:
T
The element to locate in the HashSet(Of T) object.
Return Value
Type: System.Booleantrue if the HashSet(Of T) object contains the specified element; otherwise, false.
Implements
ICollection(Of T).Contains(T)This method is an O(1) operation.
The following example demonstrates how to remove values from a HashSet(Of T) collection using the Remove method. In this example, the Contains method verifies that the set contains a value before removing it.
Imports System.Collections.Generic Module Example Public Sub Main() Dim numbers As New HashSet(Of Integer)() For i As Integer = 0 To 19 numbers.Add(i) Next i ' Display all the numbers in the hash table. Console.Write("numbers contains {0} elements: ", numbers.Count) DisplaySet(numbers) ' Remove all odd numbers. numbers.RemoveWhere(AddressOf IsOdd) Console.Write("numbers contains {0} elements: ", numbers.Count) DisplaySet(numbers) ' Check if the hash table contains 0 and, if so, remove it. If numbers.Contains(0) Then numbers.Remove(0) End If Console.Write("numbers contains {0} elements: ", numbers.Count) DisplaySet(numbers) End Sub Private Function IsOdd(ByVal i As Integer) As Boolean Return ((i Mod 2) = 1) End Function Private Sub DisplaySet(ByVal coll As HashSet(Of Integer)) Console.Write("{") For Each i As Integer In coll Console.Write(" {0}", i) Next Console.WriteLine(" }") End Sub End Module ' The example displays the following output: ' numbers contains 20 elements: { 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 } ' numbers contains 10 elements: { 0 2 4 6 8 10 12 14 16 18 } ' numbers contains 9 elements: { 2 4 6 8 10 12 14 16 18 }
Universal Windows Platform
Available since 8
.NET Framework
Available since 3.5
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
Available since 8
.NET Framework
Available since 3.5
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
Show: