Timespan-class
class. Periods track the
change in the "clock time" between two date-times. They
are measured in common time related units: years, months,
days, hours, minutes, and seconds. Each unit except for
seconds must be expressed in integer values.Interval-class
object with
as.interval
or by adding it to a date-time
with "+". Periods provide a method for measuring generalized
timespans when we wish to model clock times. Periods will
attain intuitive results at this task even when leap
years, leap seconds, gregorian days, daylight savings
changes, and other events happen during the period. See
Duration-class
for an alternative way to
measure timespans that allows precise comparisons between
timespans.
Period class objects have six slots. 1) .Data, a numeric object. The apparent amount of seconds to add to the period. 2) minute, a numeric object. The apparent amount of minutes to add to the period. 3) hour, a numeric object. The apparent amount of hours to add to the period.4) day, a numeric object. The apparent amount of days to add to the period.5) month, a numeric object. The apparent amount of months to add to the period. 6) year, a numeric object. The apparent amount of years to add to the period.