title: Looping through a list from a specific key to the end of the list
body: <p>in Python how do i loop through list starting at a key and not the beginning.
  e.g.</p>
  
  <pre><code>l = ['a','b','c','d']
  </code></pre>
  
  <p>loop through <code>l</code> but starting at b e.g. <code>l[1]</code></p>