c# - 如何在 Linq 提取方法中使用 order by 和 group by？

Question

我有一个 person 列表，其中包含 person 具有 weight 和 age 属性。

Person.cs:

public class Person
{
    public int Weight { get; set; }
    public int Age { get; set; }
}

程序.cs:

List<Person> personList = new List<Person>();

personList.Add(new Person { Age = 15, Weight = 68 });
personList.Add(new Person { Age = 19, Weight = 75 });
personList.Add(new Person { Age = 17, Weight = 68 });
personList.Add(new Person { Age = 15, Weight = 55 });
personList.Add(new Person { Age = 15, Weight = 53 });
personList.Add(new Person { Age = 17, Weight = 88 });
personList.Add(new Person { Age = 19, Weight = 45 });
personList.Add(new Person { Age = 20, Weight = 88 });

//Grouped person list 
List<People> GroupedPersonList = new List<People>();

GroupedPersonList = personList.OrderBy(x => x.Weight).????

应列出的元素:按age分组，每组应选择权重最高的。(我想按age排序此列表，但列表只包含那个年龄段最重的人。然后我将通过它创建一个新列表。)新的新列表应如下所示:

(GroupedPersonList 内容)=>

Age    | Weight 
-------|-------
15     | 68
17     | 88
19     | 75
20     | 88

如何在 LINQ 提取方法中执行此操作？

Answer 1

您可以像这样使用 GroupBy:

var GroupedPersonList = personList.GroupBy(x => x.Age , (key,element) => new
{
    Age = key,
    Weight = element.Max(c=>c.Weight)
});