C# Syntax - Split String into Array by Comma, Convert To Generic List, and Reverse Order

Question

What is the correct syntax for this:

IList names = \"Tom,Scott,Bob\".Split(\',\').ToList().Reverse();

What am I

Answer 1

The problem is that you're calling List.Reverse() which returns void.

You could either do:

List names = "Tom,Scott,Bob".Split(',').ToList();
names.Reverse();

or:

IList names = "Tom,Scott,Bob".Split(',').Reverse().ToList();

The latter is more expensive, as reversing an arbitrary IEnumerable involves buffering all of the data and then yielding it all - whereas List can do all the reversing "in-place". (The difference here is that it's calling the Enumerable.Reverse() extension method, instead of the List.Reverse() instance method.)

More efficient yet, you could use:

string[] namesArray = "Tom,Scott,Bob".Split(',');
List namesList = new List(namesArray.Length);
namesList.AddRange(namesArray);
namesList.Reverse();

This avoids creating any buffers of an inappropriate size - at the cost of taking four statements where one will do... As ever, weigh up readability against performance in the real use case.