Question

如何计算仅在一侧转弯的车辆数量，以及使用lambda转向两侧的车辆数量？

    public class Car
    {
        public int Id { get; set; }
        public string Name { get; set; }

        public Car(int _Id, string _Name)
        {
            Id = _Id;
            Name = _Name;
        }
    }

    public class Turn
    {
        public int Id { get; set; }
        public string Name { get; set; }

        public Turn(int _Id, string _Name)
        {
            Id = _Id;
            Name = _Name;
        }
    }

    public class CarTurn
    {
        public int Id { get; set; }
        public Car Car { get; set; }
        public Turn Turn { get; set; }

        public CarTurn(int _Id, Car _Car, Turn _Turn)
        {
            Id = _Id;
            Car = _Car;
            Turn = _Turn;
        }
    }

Car car1 = new Car(1, "VW");
Car car2 = new Car(2, "Volvo");
Car car3 = new Car(3, "BMW");

Turn left = new Turn(1, "Left");
Turn right = new Turn(2, "Right");

CarTurn ct1 = new CarTurn(1, car1, left);
CarTurn ct2 = new CarTurn(2, car1, right);
CarTurn ct3 = new CarTurn(3, car2, right);
CarTurn ct4 = new CarTurn(4, car3, left);

List<CarTurn> data = new List<CarTurn>();
data.Add(ct1);
data.Add(ct2);
data.Add(ct3);
data.Add(ct4);

在这种情况下结果应为：

一方：2
双方：1

修改

var groups = data.GroupBy(x => x.Car.Id);
var bothSides = groups.Count(g=> g.Any(x=> x.Turn.Id == 1) && g.Any(x=> x.Turn.Id == 2));
var oneSide = groups.Count(g=> (g.Any(x=> x.Turn.Id == 1) && !g.Any(x=> x.Turn.Id == 2))
                            || (!g.Any(x=> x.Turn.Id == 1) && g.Any(x=> x.Turn.Id == 2)));

这是回归：

双方：1 oneSide：0

Answer 1

像这样的东西（属性名称想象）：

var groups = data.GroupBy(x => x.CarId);
var bothSides = groups.Count(g=> g.Any(x=> x.IsLeftTurn) && g.Any(x=> x.IsRightTurn);
var oneSide = groups.Count(g=> (g.Any(x=> x.IsLeftTurn) && !g.Any(x=> x.IsRightTurn))
                                || (!g.Any(x=> x.IsLeftTurn) && g.Any(x=> x.IsRightTurn);

Answer 2

var carTurns = new[] { ct1, ct2, ct3, ct4 };
var groupedCarTurns = carTurns.GroupBy(ct => ct.Car);
var oneSideCount = groupedCarTurns.Count(group =>
    group.All(ct => ct.Turn == right) ||
    group.All(ct => ct.Turn == left);
var bothSides = groupedCarTurns.Count(group =>
    group.Any(ct => ct.Turn == right) &&
    group.Any(ct => ct.Turn == left);

C＃lambda group查询有两个参数？

2 个答案: