title: Python2.7 - list.remove(item) within a loop gives unexpected behaviuor
body: <p>I want to remove all even numbers in a list. But something confused me...
  This is the code.</p>
  
  <pre><code>lst = [4,4,5,5]
  
  for i in lst:
      if i % 2 == 0:
          print i
          lst.remove(i)
  
  print lst
  </code></pre>
  
  <p>It prints [4, 5, 5]  Why not [5, 5]?</p>