title: pandas vectorized operation to get the length of string
body: <p>I have a pandas dataframe.</p>
  
  <pre><code>df = pd.DataFrame(['Donald Dump','Make America Great Again!','Donald Shrimp'],
                     columns=['text'])
  </code></pre>
  
  <p>What I like to have is another column in Dataframe which has the length of the strings in the 'text' column.</p>
  
  <p>For above example, it would be </p>
  
  <pre><code>                        text  text_length
  0                Donald Dump           11
  1  Make America Great Again!           25
  2              Donald Shrimp           13
  </code></pre>
  
  <p>I know I can loop through it and get the length but is there any way to vectorize this operation? I have few million rows.</p>