what is the difference in List<string> and IEnumerable<string>
<p>These two seem to be doing the exact thing. I timed them - knowing this is a small example - but they seem to run at the exact same speed as well. Is there a benefit of using one over the other?</p>



<pre><code>List&lt;string&gt; alpha = new List&lt;string&gt;(new string[] { "a", "b", "c" });
foreach (var letter in alpha)
{
    Console.WriteLine(letter);
}

IEnumerable&lt;string&gt; _alpha = new[] {"a", "b", "c"};
foreach(var _letter in _alpha)
{
     Console.WriteLine(_letter);
}
</code></pre>
