title: Dataframe - convert rows to columns - grouped by another columns
body: <p>I am looking to convert a data frame as below</p>
  <p>Original dataset</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th>Group</th>
  <th>Miles</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td>A</td>
  <td>23</td>
  </tr>
  <tr>
  <td>A</td>
  <td>20</td>
  </tr>
  <tr>
  <td>A</td>
  <td>24</td>
  </tr>
  <tr>
  <td>A</td>
  <td>25</td>
  </tr>
  <tr>
  <td>B</td>
  <td>12</td>
  </tr>
  <tr>
  <td>B</td>
  <td>17</td>
  </tr>
  <tr>
  <td>B</td>
  <td>16</td>
  </tr>
  <tr>
  <td>B</td>
  <td>19</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>I want to convert from above format to this :</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th>Col_A</th>
  <th>Col_B</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td>23</td>
  <td>12</td>
  </tr>
  <tr>
  <td>20</td>
  <td>17</td>
  </tr>
  <tr>
  <td>24</td>
  <td>16</td>
  </tr>
  <tr>
  <td>25</td>
  <td>19</td>
  </tr>
  </tbody>
  </table>
  </div>