title: Transform a datetime column to YYYYQx with quarter number
body: <p>Is there an easy way to transform a datetime column in python to a format of <code>YYYYQx</code>, for example <code>2018Q1</code>, <code>2018Q2</code> etc?</p>
  
  <p>I've tried this line but returns nothing</p>
  
  <pre><code>zip([list(DF_A['period'].dt.year), ['Q']*length_of_DF, list(DF_A['period'].dt.quarter)])
  </code></pre>