Question

我有一个person列表，其中person包含weight和age属性。

Person.cs：

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

Program.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，每组应选择最高权重。（我想按age订购此列表，但该列表仅包含最重量的人那个年龄。然后我会通过这个创建一个新的列表。）新的新列表应如下所示：

(GroupedPersonList Contents)=>

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

如何在LINQ提取方法中做到这一点？

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)
});

Answer 2

......或者喜欢

ListView<Label> list = new ListView<Label>();
ObservableList<Label> data = FXCollections.observableArrayList(
        new Label("123"), new Label("45678999"));

@Override
public void start(Stage stage) {
    VBox box = new VBox();
    Scene scene = new Scene(box, 200, 200);
    stage.setScene(scene);
    stage.setTitle("ListViewExample");
    box.getChildren().addAll(list);
    VBox.setVgrow(list, Priority.ALWAYS);

    list.setItems(data);

    list.setCellFactory(new Callback<ListView<Label>, ListCell<Label>>() {


            @Override 
            public ListCell<Label> call(ListView<Label> list) {
                ListCell<Label> cell = new ListCell<Label>() {
                    @Override
                    public void updateItem(Label item, boolean empty) {
                        super.updateItem(item, empty);
                        if (item != null) {
                            setItem(item);
                        }
                    }
                };

                return cell;
            }
        }
    );

    stage.show();
}

如何在Linq提取方法中使用order by和group by？

2 个答案: