List RemoveLast Element and returning it with T being nullable

Question

While I don't quite understand why C# doesn't provide collection methods that remove AND return elements in one command I try to write my own custom extensions ...

    public static T RemoveLast<T>(this List<T> list)
    {
        if (list.Count > 0)
        {
            var item = list[list.Count - 1];
            list.RemoveAt(list.Count - 1);
            return item;
        }
        return null;
    }

However this gives an error for the return line: Cannot convert expression type 'null' to return type 'T'.

But trying to set T to be nullable (T?) isn't possible either. How do I change this so that T can be nullable?

Answer 1

There might be different solutions to your problem. One single solution cant solve your problem

lets discuss solutions scenario wise which suits to your requirment

Scenario 1: If you want to return last element and if last element not present then you want to return default value of that datatype, then you can use return default(T);

public static T RemoveLast<T>(this List<T> list)
        {
            if (list.Count > 0)
            {
                var item = list[list.Count - 1];
                list.RemoveAt(list.Count - 1);
                return item;
            }
            return default(T);
        }

Scenario 2: If you want to make this function only for value type then you can make return value Nullable like below

public static Nullable<T> RemoveLast<T>(this List<T> list) where T:struct
        {
            if (list.Count > 0)
            {
                var item = list[list.Count - 1];
                list.RemoveAt(list.Count - 1);
                return (T)item;
            }
            return null;
        }

Here specifying T type is struct is needed since reference types are by default nullable and making them nullable not making any sense to compiler so compiler wont allow it

Answer 2

NVM, got it:

return default(T);