title: Deleting items in a zip array
body: <p>In the code below:</p>
  
  <pre><code>array_1 = ["E", "F", "B", "A"]
  array_2 = ["E", "F", "B", "E"]
  
  zip_array = array_1.zip(array_2)
  zip_array.each { |array| zip_array.delete(array) if array.uniq.length == 1 }
  zip_array # =&gt; [["F", "F"], ["E", "A"]]
  </code></pre>
  
  <p>why is <code>["F", "F"]</code> not deleted as well? Its <code>uniq.length</code> should be <code>1</code>, shouldn't it?</p>