title: How do I remove nan from a list in all columns and convert some columns containing list to string and int?
body: <p><img src="https://i.stack.imgur.com/B1AGo.png" alt="DataFrame Image" /></p>
  <p>As you can see from the picture, some column has a list of values containing nan, I want to remove those and leave with the values, then convert it to <code>string</code> or <code>int</code> depending on the column.
  For the specific row of column that look like [nan, nan] or more nan's in a list, I want to replace it with only nan.</p>
  <p><strong>For example:</strong></p>
  <pre><code>[149-1213(R.2), nan] -&gt; 149-1213(R.2)
  
  [23500, nan] -&gt; 23500
  
  [nan, nan, nan] -&gt; nan
  
  [6000] -&gt; 6000
  
  [2015-03-08 00:00:00, nan, nan] -&gt; 2015-03-08 00:00:00
  
  [nan, SERVICE CHARGE] -&gt; SERVICE CHARGE
  </code></pre>
  <p>Thank you for helping.</p>