Date: Stores time as number of days since UNIX epoch on
1970-01-01. with negative values for earlier dates.
- It is represented as an integer (however, it is not enforced in the internal representation)
- They are always printed following the rules of the current Gregorian calendar, even though the calendar was not in use a long time ago.
- It doesn't keep track of timezones, so it should not be used to truncate the time out of
sys.Date() returns an object of class