title: Extract date from string in python
body: <p>How can I extract "20151101" (as string) from "Campaign on 01.11.2015"?</p>
  
  <p>I have read this one:
  <a href="https://stackoverflow.com/questions/3276180/extracting-date-from-a-string-in-python">Extracting date from a string in Python</a>
  . But I am getting stuck when converting from Match object to string.</p>