C# 按列表分组包含另一个 class

Question

我有两个类如下：

public class result
{
    public person identity { get; set; }
}

public class person
{
    public string name { get; set; }

    public string family { get; set; }
}

我有 List<result> 其中有一些重复数据。我想通过 System.Linq.GroupBy

摆脱重复数据

我搜索了很多，我认为我找到的最佳答案是 here，所以我模拟了我的代码如下：

class Program
{
    static void Main(string[] args)
    {
        person p1 = new person();
        p1.name = "Bill"; p1.family = "Gates";
        person p2 = new person();
        p2.name = "Satoshi"; p2.family = "Nakamoto";
        person p3 = new person();
        p3.name = "AmirAli"; p3.family = "Sam";

        List<result> lst = new List<result>();
        List<List<result>> lstGrp = new List<List<result>>();

        lst.Add(new result { identity = p1 });
        lst.Add(new result { identity = p1 });
        lst.Add(new result { identity = p1 });
        lst.Add(new result { identity = p2 });
        lst.Add(new result { identity = p2 });
        lst.Add(new result { identity = p2 });
        lst.Add(new result { identity = p3 });
        lst.Add(new result { identity = p3 });
        lst.Add(new result { identity = p3 });

        lstGrp = lst
            .GroupBy(r => r.identity)
            .Select(grp => grp.ToList())
            .ToList();

        foreach (List<result> list in lstGrp)
        {
            foreach (result item in list)
            {
                Console.WriteLine(item.identity.name + " " + item.identity.family);
            }
        }
    }
}

如图所示，我在不同的结果中有重复的人，但我想在我的控制台中看到每个人一次：

但是我最后面对的是：

我应该如何更改我的代码以获得我想要的结果？

非常感谢。

Answer 1

我认为您真正要找的是“distinct”而不是“groupBy”。请参阅此处 Select distinct using linq .

https://docs.microsoft.com/en-us/dotnet/api/system.linq.enumerable.distinct?view=net-5.0

他们对 distinct 的看法：

Returns distinct elements from a sequence.

示例：

person p1 = new person();
p1.name = "Bill";
p1.family = "Gates";

person p2 = new person();
p2.name = "Satoshi";
p2.family = "Nakamoto";

person p3 = new person();
p3.name = "AmirAli";
p3.family = "Sam";

List<result> lst = new List<result>();
List<person> lstGrp = new List<person>();
lst.Add(new result{identity = p1});
lst.Add(new result{identity = p1});
lst.Add(new result{identity = p1});
lst.Add(new result{identity = p2});
lst.Add(new result{identity = p2});
lst.Add(new result{identity = p2});
lst.Add(new result{identity = p3});
lst.Add(new result{identity = p3});
lst.Add(new result{identity = p3});

lstGrp = lst.Select(r => r.identity).Distinct().ToList();
foreach (var item in lstGrp)
{
    Console.WriteLine(item.name + " " + item.family);
}

Answer 2

您已将所有 Name 和 Family 分配给同一个变量 p1

C# 按列表分组包含另一个 class

C# group by a list contains another class

c#

linq

linq-group