title: How do you unstack columns in a DataFrame?
body: <p>I have a DataFrame, 'df' and have 53 different columns and 1740 rows. The columns include; 'Age', 'RaceOne', 'RaceTwo', 'RaceThree', 'Name', 'Identity' .. etc. But I want to reorganize the DataFrame so that a new variable 'RaceTimes' replaces 'RaceOne', 'RaceTwo', 'RaceThree' and the remainder of the DataFrame columns follows suit in a particular manner, as shown in the second DataFrame below...</p>
  
  <p>Current df:</p>
  
  <pre><code>'Age'   'RaceOne'   'RaceTwo'   'RaceThree'   'Name'   'Identity'   ...   'Male/Female         
   25      15:40:00    15:35:00    15:39:00      Wendy     105888     ...    Female
   26      15:43:00    15:25:00    15:15:00      Steve     114342     ...    Male
   22      15:20:00    15:31:00    15:23:00      Ant       123553     ...    Male
  </code></pre>
  
  <p>What I'd like to see...</p>
  
  <pre><code>'Age'   'RaceTimes'   'Name'   'Identity'   ...   'Male/Female'
   25      15:40:00      Wendy    105888      ...    Female
   25      15:35:00      Wendy    105888      ...    Female
   25      15:39:00      Wendy    105888      ...    Female
   26      15:43:00      Steve    114342      ...    Male
   26      15:25:00      Steve    114342      ...    Male
   26      15:15:00      Steve    114342      ...    Male
   22      15:20:00      Ant      123553      ...    Male
   22      15:31:00      Ant      123553      ...    Male
   22      15:23:00      Ant      123553      ...    Male
  </code></pre>