title: How to combine multiple rows with different columns filled?
body: <p>Current:</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th style="text-align: left;">id</th>
  <th style="text-align: center;">step1</th>
  <th style="text-align: right;">step2</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td style="text-align: left;">1</td>
  <td style="text-align: center;">a</td>
  <td style="text-align: right;">null</td>
  </tr>
  <tr>
  <td style="text-align: left;">1</td>
  <td style="text-align: center;">null</td>
  <td style="text-align: right;">b</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>Wanted:</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th style="text-align: left;">id</th>
  <th style="text-align: center;">step1</th>
  <th style="text-align: right;">step2</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td style="text-align: left;">1</td>
  <td style="text-align: center;">a</td>
  <td style="text-align: right;">b</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>Prefer to be done in python using pandas/numpy, thank you for the help.</p>