title: List 'Except' comparison - ignore case
body: <p>I have two lists and I want to compare them and get the differences, while ignoring any case differences.</p>
  
  <p>I have used the following code to get the differences between the two lists but it does not ignore case differences.</p>
  
  <pre><code>IEnumerable&lt;string&gt; diff = list1.Except(list2);
  List&lt;string&gt; differenceList = diff.ToList&lt;string&gt;();
  </code></pre>
  
  <p>I tried this:</p>
  
  <pre><code>IEnumerable&lt;string&gt; diff = list1.Except(list2, StringComparison.OrdinalIgnoreCase);
  </code></pre>
  
  <p>but Except does not seem to be having a string case check of that sort (so error). I'm hoping there's a work around.</p>