前言：最近项目比较忙，完全没有时间写下总结笔记，今天抽出时间来写下笔记，供写后台的你来做数据处理后台代码编写的参考。

一、分组

 

var GroupForList = numberList.GroupBy(x => x).ToDictionary(a => a.Key, b => b.ToList()).ToList();

 

二、交集、并集、差集

 

 

private static List
     
       numberList = new List
      
       () { 4,5,6,8,9,11 };private static List
       
         numberListTwo = new List
        
         () { 4,5,7,15,16,12 };public static void Main(string[] args) {            var intersectList = numberList.Intersect(numberListTwo);  //交集            var str = "";            var str2 = "";            var str3 = "";            foreach (var item in intersectList)            {                str += item+",";            }            var exceptList = numberList.Except(numberListTwo);  //差集            foreach (var item in intersectList)            {                str2 += item + ",";            }            var unionList = numberList.Union(numberListTwo);   //并集            foreach (var item in unionList)            {                str3 += item + ",";            }            Console.WriteLine("交集：" + str);            Console.WriteLine("差集：" + str2);            Console.WriteLine("并集：" + str3);}
        
       
      
     

 

 三、递归

 

public static void Main(string[] args) {        Recursion(1); }static int i = 0;private static void Recursion(int number) {      Console.Write(number+",");       var newnumber = number + i;       i++;       Thread.Sleep(1000);         Recursion(newnumber); }

 

 

结语：这些就是用最简单的方法展示 各种后台数据处理时候可能要用到的方法啦。希望能帮助到初学者的你们