title: Fill one column with value of another column in pandas DataFrame
body: <p>my dataframe looks like this:</p>
  <pre><code>ID    ADDRESS                   PRICE    LOCATION
  1     NEW YORK, BROOKLYN, 1      500     NEW YORK
  2     LONDON, LONDON, 2          400     &quot; &quot;
  3     City of MANCHESTER, 3      200     &quot; &quot;
  .
  .
  </code></pre>
  <p>I would like to fill the &quot; &quot; with the value from address. I tried something like this:</p>
  <pre><code>i = 2008
  for addrs, loc in zip(addr[2008:].ADDRSS, addr[2008:].LOCATION):
       if addrs.find('NEW YORK') != -1:
            addr[i].LOCATION = 'NEW YORK'
       if addrs.find('LONDON') != -1:
            addr[i].LOCATION = 'LONDON'
       if addrs.find('PRAGUE') != -1:
            addr[i].LOCATION = 'PRAGUE'
       i = i + 1
  .
  .
  .
  </code></pre>
  <p>The location didnt fill in from certain row, so thats why there is the addr[2008:]. The locations dont change so I can have them written like that. This code returns KeyError. I dont really know, what is wrong with this, can anybody help?</p>
  <p>EDIT:</p>
  <p>Expected output should be this:</p>
  <pre><code>ID    ADDRESS                   PRICE    LOCATION
  1     NEW YORK, BROOKLYN, 1      500     NEW YORK
  2     LONDON, LONDON, 2          400     LONDON
  3     City of MANCHESTER, 3      200     MANCHESTER
  .
  .
  </code></pre>
  <p>The catch is that in the address column, there is a variety of options how the city is mentioned, so just an easy split with , wont work.</p>