Writing date and time columns

fwrite() provides several fast and consistent ways of writing date and datetime columns to files using the dateTimeAs argument. In order for you to clearly understand how this works, you will be working batrips_dates, which consists of two columns and five rows:

            start_date            end_date
1: 2014-01-01 00:14:00 2014-01-01 00:21:00
2: 2014-01-01 00:14:00 2014-01-01 00:21:00
3: 2014-01-01 00:17:00 2014-01-01 00:42:00
4: 2014-01-01 00:23:00 2014-01-01 00:50:00
5: 2014-01-01 00:23:00 2014-01-01 00:50:00