Question

I have some List:

List<int> list = new List<int> { 1, 2, 3, 4, 5 };

I want to apply some transformation to elements of my list. I can do this in two ways:

List<int> list1 = list.Select(x => 2 * x).ToList();
List<int> list2 = list.ConvertAll(x => 2 * x).ToList();

What is the difference between these two ways?

Answer 1

Select is a LINQ extension method and works on all IEnumerable<T> objects whereas ConvertAll is implemented only by List<T>. The ConvertAll method exists since .NET 2.0 whereas LINQ was introduced with 3.5.

You should favor Select over ConvertAll as it works for any kind of list, but they do the same basically.