Description of column-types used to time-stamp data

TIME: data time stamp

Time can be defined as:

  • A double.
  • Using hours, minutes format: hh:mm.

Notice that when a subject has time under the format  hh:mm, all the time are converted into relative hours, as on the following example

TIME Reconstructed time
10:00 10
10:30 10.5
14:00 14
08:59 8.983333

When there is no column-type TIME, the column-type DATE is used to time-stamp data.

Format restrictions (an exception will be thrown otherwise):

  • A data set shall not contain more than one column with the column-type TIME.
  • String “.” will not be interpreted as a repetition of the previous line and is then non-compliant with formats listed here-above.

DATE/DAT1/DAT2/DAT3: date information

The difference between all this date information corresponds to variation of date format as summarized in the following table.

Format and associated date column name
DATE DAT1 DAT2 DAT3
Day, month and year mm/dd/yy or mm/dd/yyyy dd/mm/yy or dd/mm/yyyy yy/mm/dd or yyyy/mm/dd yy/dd/mm or yyyy/dd/mm

Several points have to be noticed. First, the day month year separator should be the character “/”. Secondly, by default, when the year is coded with two digits, it is then interpreted as 20xx. For instance, using format DAT2, 41/12/07 is interpreted as December the 7th 2041.

If both a TIME column-type and a DATE column-type are present, the DATE column is considered to represent the day and the TIME column the hour within this day.

Format restrictions (an exception will be thrown otherwise):

  • A data set shall not contain more than one column-type DATE / DAT1 / DAT2 / DAT3.
  • Year, day, and month shall be integers.
  • The separator must be “/”.
  • Character “.” will not be interpreted as a repetition of the previous line but will throw an exception as any non-compliance with formats listed here-above.
  • All the lines with valid subjects (non empty ID,OCC) should be filled correctly within the same delimiter, according to the specified date format: i.e., no empty year, no empty month, no empty day, no mix of delimiters.

Timestamp summary

As can be seen there are several ways to define the timestamp of the data set depending if there is a time column or not and if there is a DATE column or not.  

TIME column present TIME column not present
DATE column present DATE column is considered to represent the day and the TIME column the hour within this day Date column is considered to represent the time
DATE column not present DATE column is considered to represent the time First regression-column will be used to timestamp data

 

What happens if neither TIME nor DATE is defined ?

We strongly encourage the user to be careful on the TIME definition. However, if there is neither TIME nor DATE column-type, first regression-column (i.e. first column with column-type X) will be used to timestamp data. Moreover, if there is neither TIME, nor DATE/REGRESSION column-type, an arbitrary time is computed.