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HashSet<T>.RemoveWhere(Predicate<T>) 方法

定義

將符合指定述詞所定義之條件的所有項目從 HashSet<T> 集合中移除。

public:
 int RemoveWhere(Predicate<T> ^ match);
public int RemoveWhere (Predicate<T> match);
member this.RemoveWhere : Predicate<'T> -> int
Public Function RemoveWhere (match As Predicate(Of T)) As Integer

參數

match
Predicate<T>

Predicate<T> 委派,定義要移除項目的條件。

傳回

已從 HashSet<T> 集合中移除的項目數。

例外狀況

matchnull

範例

下列範例示範如何使用 方法,從 HashSet<T> 集合 Remove 中移除值。 在此範例中,所有奇數整數都會從 HashSet<T> 委派所 match 指定的集合中移除。

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);

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

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

    Console.WriteLine(" }");
}

// This 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 }
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 }

備註

呼叫這個方法是 O () n 作業,其中 nCount

適用於