83 lines
2.4 KiB
C#
83 lines
2.4 KiB
C#
|
namespace Lesson7_List
|
||
|
|
{
|
||
|
|
internal class Program
|
||
|
|
{
|
||
|
|
static void Main(string[] args)
|
||
|
|
{
|
||
|
|
#region 知识点一 List的本质
|
||
|
|
//List是C#为我们封装好的一个类
|
||
|
|
//它的本质是一个可变类型的泛型数组
|
||
|
|
//List类帮助我们实现了很多方法
|
||
|
|
//比如泛型数组的增删查改
|
||
|
|
#endregion
|
||
|
|
|
||
|
|
#region 知识点二 声明
|
||
|
|
//需要引用命名空间System.Collections.Generic
|
||
|
|
List<int> list = new List<int>();
|
||
|
|
List<string> list2 = new List<string>();
|
||
|
|
#endregion
|
||
|
|
|
||
|
|
#region 知识点三 增删查改
|
||
|
|
//增
|
||
|
|
list.Add(1);
|
||
|
|
list.Add(2);
|
||
|
|
list.Add(3);
|
||
|
|
list2.Add("123");
|
||
|
|
//范围增
|
||
|
|
List<string> list3 = new List<string>();
|
||
|
|
list3.Add("456");
|
||
|
|
list2.AddRange(list3);
|
||
|
|
//插入
|
||
|
|
list.Insert(0,9999);
|
||
|
|
|
||
|
|
|
||
|
|
//删
|
||
|
|
//1.移除指定元素
|
||
|
|
list.Remove(1);
|
||
|
|
//2.移除指定位置的元素
|
||
|
|
list.RemoveAt(0);
|
||
|
|
//3.清空
|
||
|
|
list.Clear();
|
||
|
|
|
||
|
|
//查
|
||
|
|
//1.得到指定位置的元素
|
||
|
|
Console.WriteLine(list[0]);
|
||
|
|
//2.查看元素是否存在
|
||
|
|
if (list.Contains(1))
|
||
|
|
{
|
||
|
|
Console.WriteLine("存在为1的元素");
|
||
|
|
}
|
||
|
|
//3.正向查找元素位置
|
||
|
|
//找到返回位置，找不到返回-1
|
||
|
|
int index = list.IndexOf(1);
|
||
|
|
Console.WriteLine(index);
|
||
|
|
//4.反向查找元素位置
|
||
|
|
//找到返回位置，找不到返回-1
|
||
|
|
index = list.LastIndexOf(1);
|
||
|
|
Console.WriteLine(index);
|
||
|
|
|
||
|
|
//改
|
||
|
|
Console.WriteLine(list[0]);
|
||
|
|
list[0] = 99;
|
||
|
|
Console.WriteLine(list[0]);
|
||
|
|
#endregion
|
||
|
|
|
||
|
|
#region 知识点四 遍历
|
||
|
|
//长度
|
||
|
|
Console.WriteLine(list.Count);
|
||
|
|
//容量
|
||
|
|
//避免产生垃圾
|
||
|
|
Console.WriteLine(list.Capacity);
|
||
|
|
for (int i = 0; i < list.Count; i++)
|
||
|
|
{
|
||
|
|
Console.Write(list[i]);
|
||
|
|
}
|
||
|
|
foreach (Object item in list)
|
||
|
|
{
|
||
|
|
Console.WriteLine(item);
|
||
|
|
}
|
||
|
|
#endregion
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|