le="text-align:left;"> exercise </td>
   <td style="text-align:left;"> read_csv("data/ex_3.csv") %&gt;%
  mutate(x = parse_date(x, "%d %B %Y")) </td>
  </tr>
  <tr>
   <td style="text-align:left;"> controlling-column-types-15 </td>
   <td style="text-align:left;"> exercise </td>
   <td style="text-align:left;"> read_csv("data/ex_3.csv") %&gt;%
  mutate(
    x = parse_date(x, "%d %B %Y"),
    z = parse_number(z)
  ) </td>
  </tr>
  <tr>
   <td style="text-align:left;"> reading-data-from-multipl