C# |从列表中删除所有元素
列表类表示可通过索引访问的对象列表。它属于体系。集合.泛型命名空间。List 类可以用来创建不同类型的集合，如整数、字符串等。列表类还提供了搜索、排序和操作列表的方法。名单。清除方法用于从列表中移除所有元素。
属性:
- 它不同于数组。一个列表可以动态调整大小但是数组不能。
- 列表类可以接受 null 作为引用类型的有效值，并且它也允许重复元素。
- 如果计数等于容量，则列表的容量会通过重新分配内部阵列而自动增加。在添加新元素之前，现有元素将被复制到新数组中。
语法:
public void Clear ();
以下程序说明了如何从列表中删除所有元素:
例 1:
// C# program to remove all the
// elements from a List
using System;
using System.Collections.Generic;
class Geeks {
// Main Method
public static void Main()
{
// Creating a List of integers
List<int> list1 = new List<int>();
// Inserting the elements into the List
list1.Add(1);
list1.Add(4);
list1.Add(3);
list1.Add(1);
list1.Add(2);
// Displaying the count of elements
// contained in the List before
// removing all the elements
Console.Write("Number of elements in the List Before Removing: ");
// using Count property
Console.WriteLine(list1.Count);
// Removing all elements from list
list1.Clear();
// Displaying the count of elements
// contained in the List after
// removing all the elements
Console.Write("Number of elements in the List After Removing: ");
// using Count property
Console.WriteLine(list1.Count);
}
}
输出:
Number of elements in the List Before Removing: 5
Number of elements in the List After Removing: 0
例 2:
// C# program to remove all the
// elements from a List
using System;
using System.Collections.Generic;
class Geeks {
// Main Method
public static void Main()
{
// Creating a List of strings
List<string> list1 = new List<string>();
// Inserting the elements into the List
list1.Add("Welcome");
list1.Add("To");
list1.Add("Geeks");
list1.Add("for");
list1.Add("Geeks");
list1.Add("Geeks");
list1.Add("Geeks");
// Displaying the count of elements
// contained in the List before
// removing all the elements
Console.Write("Number of elements in the List Before Removing: ");
// using Count property
Console.WriteLine(list1.Count);
// Removing all elements from list
list1.Clear();
// Displaying the count of elements
// contained in the List after
// removing all the elements
Console.Write("Number of elements in the List After Removing: ");
// using Count property
Console.WriteLine(list1.Count);
}
}
输出:
Number of elements in the List Before Removing: 7
Number of elements in the List After Removing: 0
参考:
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