title: Assign new value to variable used in while loop comparison after loop is entered
body: <p>I was wondering if anything speaks against assigning a new value to a variable that is used in a comparison in a while loop after the while loop has been entered. A dummy example:</p>
  
  <pre><code>i = 0
  target = 10
  while i &lt; target:
      print i
      if i == 9:
          target = 20
      i = i + 1
  </code></pre>