Linq 交集并集等集合理论学习

Posted 2021-12-22 有翅膀的大象

   基于C#的Linq技术，如下代码整理：

 private static void Linqtest()
    
        /////1

        List<int> numbers1 = new List<int>()  5, 4, 1, 3, 9, 8, 6, 7, 12, 10 ;
        List<int> numbers2 = new List<int>()  15, 14, 11, 13, 19, 18, 16, 17, 12, 10 ;
        var newQuerty = numbers1.Concat(
        from n in numbers2
        where !numbers1.Contains(n)
        select n
        ).OrderBy(n => n);
        string count = "";
        foreach (int i in newQuerty)
        
            count += i + ",";
        
        Console.WriteLine(count);


        ///2
        List<int> list11 = new List<int>()  1, 2, 3, 4, 4, 5, 6, 6 ;
        var newlist = list11.Distinct();
        count = "";
        foreach (int i in newlist)
        
            count += i + ",";
        
        
        Console.WriteLine(count);
    
        ///3
        List<int> list12 = new List<int>()  1, 2, 3, 4, 4, 5, 6, 6 ;
        List<int> list1 = new List<int>()  5, 6, 6, 7, 8, 9 ;
        var newlist1 = list12.Union(list1);
        count = "";
        foreach (int i in newlist1)
        
            count += i + ",";

        
        Console.WriteLine(count);

        //4
        List<int> list13 = new List<int>()  1, 2, 3, 4, 4, 5, 6, 6 ;
        List<int> list133 = new List<int>()  5, 6, 6, 7, 8, 9 ;
        var newlist13 = list13.Intersect(list133);
        count = "";
        foreach (int i in newlist13)
        
            count += i + ",";

        
        Console.WriteLine(count);

        //5
        List<int> list14 = new List<int>()  1, 2, 3, 4, 4, 5, 6, 6 ;
        List<int> list144 = new List<int>()  5, 6, 6, 7, 8, 9 ;
        var newlist14 = list14.Except(list144);
        count = "";
        foreach (int i in newlist14)
        
            count += i + ",";

        
        Console.WriteLine(count);
    

　命令行执行：

 

 

　 LINQ查询操作符的Distinct、Union、Concat、Intersect、Except、Skip、Take、SkipWhile、TakeWhile、Single、SingleOrDefault、Reverse、SelectMany,Aggregate()的使用，合并两个数组,并去掉重复元素,然后排序。

   

List<int> list= new List<int>() 1,2,3,4,4,5,6,6 ;
var newlist=list.Skip (3);

List<int> list= new List<int>() 1,2,2,3,4,4,5,6,6 ;
var newlist=list.Take (3);

Skip()和Take()方法都是IEnumerable 接口的扩展方法，包括C#中的所有Collections类，如ArrayList，Queue,Stack等等，还有数组和字符串都可以调用这两个方法。

var testList = new List(); //比如 testList里面是 1,2,3,4,5,6,7,8,9,10 var result = testList.Skip(5); //返回值就是 6,7,8,9,10; 
var result = testList.Take(5); //返回值就是 1,2,3,4,5
 //搭配使用，一般用来分页 
var result = list.Skip(2).Take(2); //返回值 3,4

　　so:如果你刻意练习某件事情请超过10000小时，那么你就会达到世界级别。

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