title: Scala: filter Seq[] (make a diff)
body: <p>I have two <code>Seq[_]</code>es in my Play application. </p>
  
  <p>Now I want to make a diff of those and get as a result an Seq with all items which are not in the other one.</p>
  
  <p>I tried to use <code>.filter()</code> but I don't know if thats a good way</p>
  
  <p>How can I achieve this?</p>
  
  <p>thanks in advance</p>
  
  <p><strong>Update</strong> ... PseudoCode Example</p>
  
  <p>I have two <code>Seq[]</code></p>
  
  <p>1.) Seq[CarsInStock]
  Attributes[ID, Brand, Color]
  <code>[{1,Porsche,Red},{3,Mercedes,Blue}]</code></p>
  
  <p>2.) Seq[CarsAfterSale]
  Attributes[ID, Brand, Color,Doors,Windows]
  <code>[{1,Porsche,Red,4,10}]</code></p>
  
  <p>Now I wan't to make a diff between the two <code>seq[]</code>. As result I want to get the Object <code>{3,Mercedes,Blue}]</code> because it is in stock, but after sales I have to know which ones I have to remove from stock.
  I want to recognize the difference by the <code>ID</code> of the elements</p>