[英]Sort List of objects by the number subtypes in VB.NET
我有一辆基本的 class vehicle
,并列出了不同的子类( Car,Motorbike, Bicycle
)。 现在,我想获取列表中对象的每个子类的数量,按降序排序。
Dim ListOfVehicle = New List(Of Vehicle)
ListOfVehicle.Add(New Car(50, "Rot", "Mercedes"))
ListOfVehicle.Add(New Car(70, "Grün", "Audi"))
ListOfVehicle.Add(New Car(20, "Violet", "Tesla"))
ListOfVehicle.Add(New Car(150, "Blau", "BMW"))
ListOfVehicle.Add(New Motorbike(70, "Grün", "Kawasaki"))
ListOfVehicle.Add(New Motorbike(120, "Rot", "Honda"))
ListOfVehicle.Add(New Motorbike(200, "Pink", "BMW"))
ListOfVehicle.Add(New Bicycle(20, "Blau", "Cube"))
ListOfVehicle.Add(New Bicycle(250, "Orange", "BMC"))
output 应如下所示:
车 - 4
摩托车 - 3
自行车 - 2
使用ToLookup
按GetType
键计数并按降序排序。 然后 output 使用Key
属性和Count()
方法:
Dim lookup = ListOfVehicle.ToLookup(Function(x) x.[GetType]()).OrderByDescending(Function(x) x.Count())
For each vehicle in lookup
Console.WriteLine(vehicle.Key.ToString() + " - " + vehicle.Count().ToString())
Next
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