trunc.POSIXt: return the floor, ceiling, or rounded value of date or time to
specified unit.
Description
trunc.POSIXt returns the date truncated to the specified unit.
ceiling.POSIXt returns next ceiling of the date at the unit selected in
units.
floor.POSIXttrunk.POSIXt by another name.
round.POSIXt returns the date or time value rounded to nearest
specified unit selected in digits.
trunc.POSIXt and round.POSIXt have been extended from
the base package functions.