title: Multiply values of same column with same id
body: <p>There is a table like this:</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th>ID</th>
  <th>Value</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td>1</td>
  <td>0.2</td>
  </tr>
  <tr>
  <td>2</td>
  <td>0.55</td>
  </tr>
  <tr>
  <td>1</td>
  <td>0.4</td>
  </tr>
  <tr>
  <td>3</td>
  <td>0.6</td>
  </tr>
  <tr>
  <td>1</td>
  <td>0.4</td>
  </tr>
  <tr>
  <td>...</td>
  <td>...</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>I want to multiply Values where I have the same ID.</p>
  <p>So that I get a table looking like this:</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th>ID</th>
  <th>Value</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td>1</td>
  <td>0.032</td>
  </tr>
  <tr>
  <td>2</td>
  <td>0.55</td>
  </tr>
  <tr>
  <td>1</td>
  <td>0.032</td>
  </tr>
  <tr>
  <td>3</td>
  <td>0.6</td>
  </tr>
  <tr>
  <td>1</td>
  <td>0.032</td>
  </tr>
  <tr>
  <td>...</td>
  <td>...</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>Unfortunately I have no point where to start for this that makes sense...</p>