title: array with only non duplicate values
body: <p>This is not a problem, but more of a question if there are other ways to do this:</p>
  
  <p>I have an array:</p>
  
  <pre><code>arr = [1,2,3,4,4,5,1,4,3]
  </code></pre>
  
  <p>I want this output: <code>[2,5]</code></p>
  
  <p>My code looks like this:</p>
  
  <pre><code>arr.select { |e| arr.count(e) == 1}
  </code></pre>
  
  <p>Are there some alternatives to this?</p>