/p></td>
      </tr><tr><td>
          <p><code><a href="na_if.html">na_if()</a></code> </p>
        </td>
        <td><p>Convert values to <code>NA</code></p></td>
      </tr><tr><td>
          <p><code><a href="nest_by.html">nest_by()</a></code> </p>
        </td>
        <td><p>Nest data.tables</p></td>
      </tr><tr><td>
          <p><code><a href="nest_join.html">nest_join()</a></code> </p>
        </td>
        <td><p>Nest join</p></td>
      </tr><tr><td>
          <p><code><a href="pick.html">pick(