title: How can you insert a colon every two characters?
body: <p>I have a column of time values, except that they are in character format and do not have the colons to separate H, M, S.  The column looks similar to the following:</p>
  
  <pre><code>Time
  024201
  054722
  213024
  205022
  205024
  125440 
  </code></pre>
  
  <p>I want to convert all the values in the column to look like actual time values in the format <code>H:M:S</code>.  The values are already in <code>HMS</code> format, so it is simply a matter of inserting colons, but that is proving more difficult than I thought.  I found a package that adds commas every three digits from the right to make Strings look like currency values, but nothing for time (without also adding a date value, which I do not want to do).  Any help would be appreciated.</p>