HashSet<T>.Contains(T) HashSet<T>.Contains(T) HashSet<T>.Contains(T) HashSet<T>.Contains(T) Method

Définition

Détermine si un objet HashSet<T> contient l'élément spécifié.Determines whether a HashSet<T> object contains the specified element.

public:
 virtual bool Contains(T item);
public bool Contains (T item);
abstract member Contains : 'T -> bool
override this.Contains : 'T -> bool
Public Function Contains (item As T) As Boolean

Paramètres

item
T T T T

Élément à rechercher dans l'objet HashSet<T>.The element to locate in the HashSet<T> object.

Retours

true si l'objet HashSet<T> contient l'élément spécifié ; sinon, false.true if the HashSet<T> object contains the specified element; otherwise, false.

Implémente

Exemples

L’exemple suivant montre comment supprimer des valeurs d’une HashSet<T> collection à l' Remove aide de la méthode.The following example demonstrates how to remove values from a HashSet<T> collection using the Remove method. Dans cet exemple, la Contains méthode vérifie que l’ensemble contient une valeur avant de le supprimer.In this example, the Contains method verifies that the set contains a value before removing it.

using System;
using System.Collections.Generic;

class Example
{
    static void Main()
    {
        HashSet<int> numbers = new HashSet<int>();

        for (int i = 0; i < 20; i++) {
            numbers.Add(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(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)) {
            numbers.Remove(0);
        }
        Console.Write("numbers contains {0} elements: ", numbers.Count);
        DisplaySet(numbers);
    }

    private static bool IsOdd(int i)
    {
        return ((i % 2) == 1);
    }

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

        Console.WriteLine(" }");
    }
}
// This example display 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 }
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 }

Remarques

Cette méthode est une opération O (1).This method is an O(1) operation.

S’applique à