title: Only else-block of "if let"?
body: <p>In a <code>cellForRowAtIndexPath</code> I have:</p>
  
  <pre><code>if let imageView = cell.viewWithTag(SOME_TAG) as? UIImageView
  {
      // Nothing to do here.
  }
  else
  {
      // Add image view to cell.
  }
  </code></pre>
  
  <p>but I only need the <code>else</code> block. Is there a way to invert a <code>if let xyz =</code>?</p>
  
  <p>(I know I could break it up and have a <code>if imageView == nil</code>.) </p>
  
  <p>Just found <a href="https://stackoverflow.com/questions/27412735/if-not-let-in-swift?noredirect=1&amp;lq=1">this similar question</a>.</p>