title: Length of longest word in a list
body: <p>What is the more pythonic way of getting the length of the longest word:</p>
  
  <p><code>len(max(words, key=len))</code></p>
  
  <p>Or:</p>
  
  <p><code>max(len(w) for w in words)</code></p>
  
  <p>Or.. something else?   <code>words</code> is a list of strings. 
  I am finding I need to do this often and after timing with a few different sample sizes the first way seems to be consistently faster, despite seeming less efficient at face value (the redundancy of <code>len</code> being called twice seems not to matter - does more happen in C code in this form?).  </p>