title: Join List<string> Together with Commas Plus "and" for Last Element
body: <p>I know I could figure a way out but I am wondering if there is a more concise solution. There's always <code>String.Join(", ", lList)</code> and <code>lList.Aggregate((a, b) =&gt; a + ", " + b);</code> but I want to add an exception for the last one to have <code>", and "</code> as its joining string. Does <code>Aggregate()</code> have some index value somewhere I can use? Thanks.</p>