title: Retrieve name of column from its Index in Pandas
body: <p>I have a pandas dataframe and a numpy array of values of that dataframe.
  I have the index of a specific column and I already have the row index of an important value. Now I need to get the column name of that particular value from my dataframe.</p>
  
  <p>After searching through the documentations, I found out that I can do the opposite but not what I want. </p>