Convert IEnumerable<IEnumerable<T>> to List<List<T>>

Question

How do I convert a IEnumerable<IEnumerable<T>> to a 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

May be like this:

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