title: python find difference between two lists
body: <p>I am new to programming but I keep learning, and recently I hit the wall so I'm asking for help.
  Sorry if this was discussed before, but I can't find answer to my problem. 
  I have two lists. And I need to compare them, and in the result to get the objects that <strong>DON'T match.</strong> For example:</p>
  
  <pre><code>a = [1,2,3,4,5,6]
  b = [1,2,3,4,5,6,7,8,9]
  result = [7,8,9].
  </code></pre>
  
  <p>And I only seem to find code and examples that return matches. Which I don't need.</p>
  
  <p>Lists are in file <strong>notepad file.txt</strong> for you folks to keep in mind if you this helps you to help me. :)</p>