t-align:left;"> read_csv(
  "data/test_3.csv",
  col_names = c("a", "b", "c"),
  col_types = cols(
    a = col_double(),
    b = col_double(),
    c = col_double()
  )
) </td>
  </tr>
  <tr>
   <td style="text-align:left;"> reading-data-from-a-file-18 </td>
   <td style="text-align:left;"> exercise </td>
   <td style="text-align:left;"> read_csv("data/test_5.csv", na = ".") </td>
  </tr>
  <tr>
   <td style="text-align:left;"> reading-data-from-a-file-19 </td>
   <td style="text-align:left;