title: Python : find max value and index of a list of list of list
body: <p>I have a list of list of list in python, which looks like this :</p>
  
  <pre><code>my_list = [ [[1,2,3],[4,3,2]] , [[2,1,9],[8,1,2]] , [[5,4,3],[1,6,7]] , ...]
  </code></pre>
  
  <p>would like to retrieve the max value of the list and its three indices.</p>
  
  <p>I have seen how to do it for a list of list :</p>
  
  <pre><code>max_value, max_index = max((x, (i, j))
                             for i, row in enumerate(my_list)
                             for j, x in enumerate(row))
  </code></pre>
  
  <p>but I don't understand how to adapt it for a 3rd list.</p>
  
  <hr>
  
  <p><strong>Another question</strong> : Is there an easy way to apply the following operation on all the elements of my list ? </p>
  
  <pre><code>my_list = my_list - my_list[0] * 2
  </code></pre>