title: Comparing two lists and return not matching items results with error
body: <p>I tried to compare two lists by using the <code>Except</code> method. But when I did, I got an error saying:</p>
  <blockquote>
  <p>Cannot convert from 'Systems.Collections.Generic.List&lt;&gt;' to 'System.Linq.IQueryable&lt;&gt;'</p>
  <p>'System.Collections.Generic.List&lt;&gt; does not contain a definition for 'Except' and the best extension method overload 'System.Linq.Queryable.Except(System.Linq.IQueryable, System.Collections.GEneric.IEnumerable)' has some invalid arguments</p>
  </blockquote>
  <p>I also experienced this when I tried <code>Intersect</code>. I'm trying to compare Sent list and Result list (code and list shown below) and return items that does not have any match. So when I googled for how to do so, I came across the Except method as well as the Intersect.</p>
  <pre><code>public class Sent
  {
      public string Address;
      public string Data;
  }
  
  public class Result
  {
      public string AddressOK;
      public string DataOK;
  }
  
  
  
  var sent = new List&lt;Sent&gt;();
  sent.Add(new Sent() { Address = linaddr1, Data = lindat1 });
  var res = new List&lt;Result&gt;();
  res.Add( new Result() { AddressOK = linaddr2, DataOK = lindat2 } );
  //linaddr1 and 2, lindat1 and 2 contains the address and data shown in the list below
  //taken from another part of the entire program
  </code></pre>
  <p>The lists look like such:</p>
  <pre><code>sent                       res
  Address    Data            Address        Data
  04004C     55AA55          04004C         55AA55
  040004     0720            040004         0720
  040037     30           
  04004A     FFFF            04004A         FFFF
  </code></pre>
  <p>I only tried using this code:
  <code>var diff = sent.Except(res).ToList()</code>
  but as I've mentioned, it results with the aforementioned errors above.</p>
  <p>EDIT: I edited the list. Sorry for that. It's just only a matter of the res list missing one or two or more items from the original list and then comparing both lists to see which item/s is/are missing from the res list.</p>