title: Select last chars of string until whitespace in Python
body: <p>Is there any efficient way to select the last characters of a string until there's a whitespace in Python?</p>
  
  <p>For example I have the following string:</p>
  
  <pre><code>str = 'Hello my name is John'
  </code></pre>
  
  <p>I want to return 'John'. But if the str was:</p>
  
  <pre><code>str = 'Hello my name is Sally'
  </code></pre>
  
  <p>I want to retrun 'Sally'</p>