将IEnumerable <IEnumerable <T >>转换为List <List <T >>

Question

如何将IEnumerable<IEnumerable<T>>转换为List<List<T>> ？

Answer 1

How about this ...

IEnumerable<IEnumerable<int>> input = ...
List<List<int>> nestedList = input.Select(i => i.ToList()).ToList();

Answer 2

Using combination of the List(IEnumerable) constructor and Linq:

List<List<T>> DoIt<T>(IEnumerable<IEnumerable<T>> items)
{
    return new List<List<T>>(items.Select((x) => x.ToList()));
}

Answer 3

可能是这样的：

var test2 = test.ToList().ConvertAll(x => x.ToList());

Answer 4

You might want to think why you are trying to do this. If it is because you have an enumerable of enumerables that have been returned by a LINQ query that you then want to refer to by an index, perhaps LINQ is not the most appropriate way to generate the data structure you want. Maybe you should refactor with methods that return lists rather than enumerables.