title: different format of time - how to read it in? R, readr
body: <p>I've got a file which includes the column with the recorded time of the event. Sometimes the time is in a format mm:ss and sometimes it has additional zeros at the end - mm:ss:00. See example below:</p>
  
  <pre><code>id    time
  1     20:50
  2     76:58:00
  3     56:13:00
  4     03:44
  </code></pre>
  
  <p>When I am reading this data in using <code>read_csv</code> all the values in a shorter format (mm:ss) are marked as <code>NA</code>. When I set this values to be read in as strings using <code>read_csv('data.csv', col_types = cols(time = col_character()))</code> all the values are changed to shorter format (so I've got <code>76:58</code> in the second row). How can I parse this <code>time</code> column to have all the data in one format (no matter if shorter or longer one), but as <code>time</code> type of variable and without loosing the data for these inputs which are in shorter format? </p>
  
  <p>Why exactly all 8-character values are replaced with 'NA' while parsing as time?</p>