What is the correct syntax for this:
IList<string> names = "Tom,Scott,Bob".Split(',').ToList<string>().Reverse();
What am I messing up? What does TSource mean?
The problem is that you're calling List<T>.Reverse()
which returns void
.
You could either do:
List<string> names = "Tom,Scott,Bob".Split(',').ToList<string>();
names.Reverse();
or:
IList<string> names = "Tom,Scott,Bob".Split(',').Reverse().ToList<string>();
The latter is more expensive, as reversing an arbitrary IEnumerable<T>
involves buffering all of the data and then yielding it all - whereas List<T>
can do all the reversing "in-place". (The difference here is that it's calling the Enumerable.Reverse<T>()
extension method, instead of the List<T>.Reverse()
instance method.)
More efficient yet, you could use:
string[] namesArray = "Tom,Scott,Bob".Split(',');
List<string> namesList = new List<string>(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.