HashSet<T>.ExceptWith(IEnumerable<T>) Method

public:
 virtual void ExceptWith(System::Collections::Generic::IEnumerable<T> ^ other);

public:
 void ExceptWith(System::Collections::Generic::IEnumerable<T> ^ other);

public void ExceptWith(System.Collections.Generic.IEnumerable<T> other);

abstract member ExceptWith : seq<'T> -> unit
override this.ExceptWith : seq<'T> -> unit

member this.ExceptWith : seq<'T> -> unit

Public Sub ExceptWith (other As IEnumerable(Of T))

Parameters

Implements

Exceptions

Examples

The following example creates two HashSet<T> collections with overlapping sets of data. The lower range of values is then removed from the larger set using the ExceptWith method.

HashSet<int> lowNumbers = new HashSet<int>();
HashSet<int> highNumbers = new HashSet<int>();

for (int i = 0; i < 6; i++)
{
 lowNumbers.Add(i);
}

for (int i = 3; i < 10; i++)
{
 highNumbers.Add(i);
}

Console.Write("lowNumbers contains {0} elements: ", lowNumbers.Count);
DisplaySet(lowNumbers);

Console.Write("highNumbers contains {0} elements: ", highNumbers.Count);
DisplaySet(highNumbers);

Console.WriteLine("highNumbers ExceptWith lowNumbers...");
highNumbers.ExceptWith(lowNumbers);

Console.Write("highNumbers contains {0} elements: ", highNumbers.Count);
DisplaySet(highNumbers);

void DisplaySet(HashSet<int> set)
{
 Console.Write("{");
 foreach (int i in set)
 {
 Console.Write(" {0}", i);
 }
 Console.WriteLine(" }");
}

/* This example provides output similar to the following:
* lowNumbers contains 6 elements: { 0 1 2 3 4 5 }
* highNumbers contains 7 elements: { 3 4 5 6 7 8 9 }
* highNumbers ExceptWith lowNumbers...
* highNumbers contains 4 elements: { 6 7 8 9 }
*/

let displaySet (set: HashSet<int>) =
 printf "{"

 for i in set do
 printf $" {i}"

 printfn " }"

let lowNumbers = HashSet<int>()
let highNumbers = HashSet<int>()

for i = 0 to 5 do
 lowNumbers.Add i |> ignore

for i = 3 to 9 do
 highNumbers.Add i |> ignore

printf $"lowNumbers contains {lowNumbers.Count} elements: "
displaySet lowNumbers

printf $"highNumbers contains {highNumbers.Count} elements: "
displaySet highNumbers

printfn "highNumbers ExceptWith lowNumbers..."
highNumbers.ExceptWith(lowNumbers)

printf $"highNumbers contains {highNumbers.Count} elements: "
displaySet highNumbers
// This example provides output similar to the following:
// lowNumbers contains 6 elements: { 0 1 2 3 4 5 }
// highNumbers contains 7 elements: { 3 4 5 6 7 8 9 }
// highNumbers ExceptWith lowNumbers...
// highNumbers contains 4 elements: { 6 7 8 9 }

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

 Console.Write("lowNumbers contains {0} elements: ", lowNumbers.Count)
 DisplaySet(lowNumbers)

 Console.Write("highNumbers contains {0} elements: ", highNumbers.Count)
 DisplaySet(highNumbers)

 Console.WriteLine("highNumbers ExceptWith lowNumbers...")
 highNumbers.ExceptWith(lowNumbers)

 Console.Write("highNumbers contains {0} elements: ", highNumbers.Count)
 DisplaySet(highNumbers)

End Sub
' This example provides output similar to the following:
' lowNumbers contains 6 elements: { 0 1 2 3 4 5 }
' highNumbers contains 7 elements: { 3 4 5 6 7 8 9 }
' highNumbers ExceptWith lowNumbers...
' highNumbers contains 4 elements: { 6 7 8 9 }

Remarks

The ExceptWith method is the equivalent of mathematical set subtraction.

This method is an O(n) operation, where n is the number of elements in the other parameter.