lambda expression C＃从List中获取不匹配的记录 [英] lambda expression C# to get the unmatched record from a List

问题描述

我有一个list1 = {1,1,2,3,4,5}



我要比较列表中的项目。



我的代码：

var list2 = list1.GroupBy（c => c.action）。选择（g => g.FirstOrDefault（））。ToList（）;



现在我有一个新的list2 = {1 ，1,2}

i想要从这个列表中获得2分。





或者如果是List = {1,1}

我想得到1分。



有什么建议吗？

Hi,

I have a list1 = {1,1,2,3,4,5}

I want to compare the items in the list.

My code:
var list2 = list1.GroupBy(c => c.action).Select(g => g.FirstOrDefault()).ToList();

Now i have a new list2 = {1,1,2}
i want to get a 2 out of this list.


or if List ={1,1}
I want to get 1 out of it.

Any suggestions, please?

推荐答案

你不需要lambda - 只需使用Linq方法：

You don''t need a lambda - just use Linq methods:

List<int> list1 = new int[] { 1, 1, 2, 3, 4, 5 }.ToList();
List<int> list2 = new int[] { 1, 1, 2 }.ToList();


var result = list1.Intersect(list2);
foreach (int i in result) Console.WriteLine(i);

int[] arr = new int[] { 1, 1, 2 };
//Create a dictionary where the key is each int occurance
//and the value is the number of int occurances.
Dictionary<int, int> dict = arr.Distinct().ToDictionary(i => i, i => arr.Where(ii=>ii==i).Count());
//now do what you like with it.. 
//eg get me the value that occurs least often, 
//which I think is what you're after:
int r=dict[dict.Values.Min()];

ATG

ATG

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