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

Definition

Namespace:

System.Collections.Generic

Assembly:

System.Collections.dll

Source:

HashSet.cs

Modifies the current HashSet<T> object to contain only elements that are present either in that object or in the specified collection, but not both.

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

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

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

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

Parameters

other

IEnumerable<T>

The collection to compare to the current HashSet<T> object.

Implements

SymmetricExceptWith(IEnumerable<T>)

Exceptions

ArgumentNullException

other is null.

Examples

The following example creates two HashSet<T> collections with overlapping sets of data. The set that contains the lower values is then modified, using the SymmetricExceptWith method, to contain only the values that are not present in both sets.

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("lowNumbers SymmetricExceptWith highNumbers...");
lowNumbers.SymmetricExceptWith(highNumbers);

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

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 }
* lowNumbers SymmetricExceptWith highNumbers...
* lowNumbers contains 7 elements: { 0 1 2 8 7 6 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 in 0..5 do
    lowNumbers.Add i |> ignore

for i in 3..9 do
    highNumbers.Add i |> ignore

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

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

printfn "lowNumbers SymmetricExceptWith highNumbers..."
lowNumbers.SymmetricExceptWith highNumbers

printf $"lowNumbers contains {lowNumbers.Count} elements: "
displaySet lowNumbers
// 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 }
//    lowNumbers SymmetricExceptWith highNumbers...
//    lowNumbers contains 7 elements: { 0 1 2 8 7 6 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("lowNumbers SymmetricExceptWith highNumbers...")
    lowNumbers.SymmetricExceptWith(highNumbers)

    Console.Write("lowNumbers contains {0} elements: ", lowNumbers.Count)
    DisplaySet(lowNumbers)
End Sub
' This example produces 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 }
' lowNumbers SymmetricExceptWith highNumbers...
' lowNumbers contains 7 elements: { 0 1 2 8 7 6 9 }

Remarks

If the other parameter is a HashSet<T> collection with the same equality comparer as the current HashSet<T> object, this method is an O(n) operation. Otherwise, this method is an O(n + m) operation, where n is the number of elements in other and m is Count.