C# 泛型集合类List<T>使用总结

public class MyComparer : IEqualityComparer<Person>
{
    public bool Equals([AllowNull] Person x, [AllowNull] Person y)
    {
        return x.name == y.name && x.age == y.age;
    }

    public int GetHashCode([DisallowNull] Person obj)
    {
        return obj.name.GetHashCode() + obj.age.GetHashCode();
        //return obj.name.GetHashCode() ^ obj.age.GetHashCode();// 两种写法都可以
    }
}

public class MyComparer : IEqualityComparer<Person>
{
    public bool Equals([AllowNull] Person x, [AllowNull] Person y)
    {
        if(x == null || y == null) return false;
        if(x.name == y.name && x.age == y.age) return true;
        return false;
    }

    public int GetHashCode([DisallowNull] Person obj)
    {
        if(obj == null) return 0;
        return obj.name.GetHashCode() + obj.age.GetHashCode();
        //return obj.name.GetHashCode() ^ obj.age.GetHashCode();// 两种写法都可以
    }
}

using System;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Linq;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            //交集：集合A.Intersect(集合B)
            var _old = new List<Person> {
                new Person{name="zs",age=21},
                new Person{name="ls",age=10},
                new Person{name="ww",age=13},
                new Person{name="ls",age=10},
                new Person{name="ww",age=13}
            };
            var _new = new List<Person> {
                new Person{name="zs",age=21},
                new Person{name="ls",age=31},
                new Person{name="ww3",age=13}
            };
            var _obj = _old.Intersect(_new,new MyComparer()).ToList();
            for (int i = 0; i < _obj.Count; i++)
            {
                var x = _obj[i];
                Console.WriteLine("name:{0},age:{1}", x.name, x.age);
                //结果： name:zs,age:21
            }
            Console.ReadLine();
        }
    }
    public class Person
    {
        public string name { get; set; }
        public int age { get; set; }
    }
}

var _oj2 = _old.Except(_new, new MyComparer()).ToList();

//结果：
name:ls,age:10
name:ww,age:13

var _oj2 = _old.Union(_new, new MyComparer()).ToList();

//结果：
name:zs,age:21
name:ls,age:10
name:ww,age:13
name:ls,age:31
name:ww3,age:13

var _oj2 = _old.Distinct(new MyComparer()).ToList();

//结果：
name:zs,age:21
name:ls,age:10
name:ww,age:13