C＃|从HashSet中删除所有元素

HashSet是唯一元素的无序集合。它位于System.Collections.Generic命名空间下。它用于我们要防止将重复项插入到集合中的情况。就性能而言，与列表相比更好。哈希集。清除方法用于从HashSet对象中删除所有元素。

句法：

mySet.Clear(); 

在这里， mySet是HashSet的名称。

下面给出了一些示例，以更好地理解实现：

范例1：

// C# code to remove all elements from HashSet
using System;
using System.Collections.Generic;
  
class GFG {
  
    // Driver code
    public static void Main()
    {
  
        // Creating a HashSet of integers
        HashSet mySet = new HashSet();
  
        // Inserting even numbers less than
        // equal to 20 in HashSet mySet1
        for (int i = 0; i < 10; i++) {
            mySet.Add(i * 2);
        }
  
        // Displaying the number of elements in HashSet
        Console.WriteLine(mySet.Count);
  
        // Removing all the elements from HashSet
        mySet.Clear();
  
        // Displaying the number of elements in HashSet
        // after removing all the elements from it
        Console.WriteLine(mySet.Count);
    }
}

输出：

10
0

范例2：

// C# code to remove all elements from HashSet
using System;
using System.Collections.Generic;
  
class GFG {
  
    // Driver code
    public static void Main()
    {
  
        // Creating a HashSet of strings
        HashSet mySet = new HashSet();
  
        // Inserting elements in HashSet
        mySet.Add("Geeks");
        mySet.Add("and");
        mySet.Add("GeeksforGeeks");
        mySet.Add("are");
        mySet.Add("the");
        mySet.Add("best");
  
        // Displaying the number of elements in HashSet
        Console.WriteLine(mySet.Count);
  
        // Removing all the elements from HashSet
        mySet.Clear();
  
        // Displaying the number of elements in HashSet
        // after removing all the elements from it
        Console.WriteLine(mySet.Count);
  
        // Inserting elements in HashSet
        mySet.Add("Join");
        mySet.Add("Geeks");
        mySet.Add("Classes");
  
        // Displaying the number of elements in HashSet
        Console.WriteLine(mySet.Count);
    }
}

输出：

6
0
3

参考：

• https://docs.microsoft.com/zh-cn/dotnet/api/system.collections.generic.hashset-1.clear?view=netframework-4.7.2