title: What to use instead of Concat in string lists in C#
body: <p>I have these lists of strings</p>
  <pre><code>List&lt;string&gt; files = new List&lt;string&gt;
                      (System.Linq.Enumerable.Concat
                      (System.IO.Directory.GetFiles(Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments), &quot;*.*&quot;),
                      System.IO.Directory.GetFiles(Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments), &quot;*.pdf&quot;)));
  </code></pre>
  <p>I want to refactor code and I want to use something more efficient or faster than concat.How can I do that?
  Thanks</p>