C# Distinct去重泛型List

• List<int>去重
• List<string>去重
• List<T>去重

1. List<int>去重

 List<int> ilist = new List<int>() { 1, 2, 3, 4, 2, 3 };

 ilist = ilist.Distinct().ToList();

 foreach (var item in ilist)

 {

    Console.WriteLine(item);

 }

2. List<string>去重

 List<string> strList = new List<string>() { "4", "4", "5", "6", "6" };

 strList = strList.Distinct().ToList();

 foreach (var item in strList)

 {

    Console.WriteLine(item);

 }

3. List<T>去重

 public class User

 {

   public int Id { get; set; }

   public string Name { get; set; }

   public int Age { get; set;}

 }

//Main方法

 List<User> list = new List<User>()

 {

    new User() { Id = 1, Name = "张三", Age = 11 } ,

    new User() { Id = 1, Name = "张三", Age = 11} ,

    new User() { Id = 3, Name = "李四", Age = 13 } ,

 };

 //方法一

 list = list.GroupBy(p => p.Id).Select(q => q.First()).ToList();

 //方法二

 list = list.GroupBy(p => p.Name).Select(q => q.First()).ToList();

 //方法三

 list = list.GroupBy(p => p.Age).Select(q => q.First()).ToList();

 foreach (var item in list)

 {

   Console.WriteLine("Id:" + item.Id + ", Name:" + item.Name + ", Age:" + item.Age);

 }

 //方法四

 var list1 = (from p in list

              group p by new { p.Id, p.Name, p.Age } into g

              select g).ToList();

 foreach (var item in list1)

 {

    Console.WriteLine("Id:" + item.Key.Id + ", Name:" + item.Key.Name + ", Age:" + item.Key.Age);

 }