title: get records & column names from dataframe where atleast one column value of a record is True
body: <p>I got a dataframe as follows:</p>
  
  <pre><code>flight_id | from_location  | to_location |  schedule |  
  1         |   Vancouver    |   Toronto   |   3-Jan   |  
  2         |   Amsterdam    |   Tokyo     |   15-Feb  |  
  4         |   None         |   Glasgow   |   12-Jan  |  
  9         |   Halmstad     |   Athens    |   21-Jan  |  
  3         |   Brisbane     |   None      |   4-Feb   |  
  4         |   Johannesburg |   Venice    |   12-Jan  |
  9         |   None         |  None       |   3-Mar   |
  </code></pre>
  
  <p>I want to get only those record index values where atleast one of the columns <code>from_location</code> ,<code>to_location</code> is <code>None</code>. Also the record index should be tupled with column name that qualified it for selection(i.e the column name whose value is <code>None</code> in that record.</p>
  
  <p>Output for above example should be like:
  <code>[(2,from_location),(4,to_location),(6,from_location),(6,to_location)]</code></p>
  
  <p>1st element in tuple: record index<br>
  2nd element in tuple: column_name in that record index whose value is <code>None</code></p>
  
  <p>I did this:- <code>df[df[['flight_id','to_location']].isnull().any(axis=1)].index.values.tolist()</code><br>
  But, that gives me only the record index values <code>[2,4,6]</code>. I also want corresponding column names as described above</p>
  
  <p>Any ideas folks?</p>