title: In-place replacement of all occurrences of an element in a list in python
body: <p>Assume I have a list:</p>
  
  <pre><code>myl = [1, 2, 3, 4, 5, 4, 4, 4, 6]
  </code></pre>
  
  <p>What is the most efficient and simplest pythonic way of <strong>in-place</strong> (<em>double emphasis</em>) replacement of all occurrences of <code>4</code> with <code>44</code>? </p>
  
  <p>I'm also curious as to why there isn't a <code>standard</code> way of doing this (especially, when <code>strings</code> have a <em>not-in-place</em> <a href="https://docs.python.org/2/library/string.html#string.replace" rel="noreferrer"><code>replace</code></a> method)?</p>