使用LINQ转换IEnumerable集合

你可以通过分组来完成。看到了吗 hooked on linq 更多样品

var result = from car in cars
             group car by car.year into g
             where g.Count() > 1
             select g

现在的结果是 IEnumerable<IGrouping<int, Car>>

foreach(var g in result)
{
    int year = g.Key;
    foreach(var car in g)
    {
        // list the cars
    }
}

请尝试以下操作

List<Car> list = null;
IEnumerable<List<Car>> ret = 
    from it in list
    group it by it.Year into g
    where g.Count() > 1 
    select g.ToList();

IEnumerable<List<Car>> carsGroupedByYear = 
    cars.GroupBy(c => c.Year) /* Groups the cars by year */
        .Where(g => g.Count() > 1) /* Only takes groups with > 1 element */
        .Select(g => g.ToList()); /* Selects each group as a List<Car> */