title: Pass a Function in Shiny to match columns in Dataframe such that cell A1 = B1
body: <p>How we can match two columns of a dataframe in R using a Name mapping sheet?</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>Tom</td>
  <td>Julie</td>
  </tr>
  <tr>
  <td>Harry</td>
  <td>Harry</td>
  </tr>
  <tr>
  <td>Cat</td>
  <td>Mouse</td>
  </tr>
  <tr>
  <td>Dog</td>
  <td>Dog</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>Such that, A1 = B1, A2 = B2 and so on:</p>
  <p>It should take values like Tom = Julie</p>