eseconds(1)
# Time difference of 1 secs
eminutes(3.5)
# Time difference of 3.5 mins
x <- as.POSIXct("2009-08-03")
# "2009-08-03 CDT"
x + edays(1) + ehours(6) + eminutes(30)
# "2009-08-04 06:30:00 CDT"
x + edays(100) - ehours(8)
# "2009-11-10 15:00:00 CST"
class(as.Date("2009-08-09") + edays(1)) # retains Date class
# "Date"
as.Date("2009-08-09") + ehours(12)
# "2009-08-09 12:00:00 UTC"
class(as.Date("2009-08-09") + ehours(12))
# "POSIXt" "POSIXct"
# converts to POSIXt class to accomodate time units
eweeks(1) - edays(7)
# Time difference of 0 secs
c(1:3) * ehours(1)
# Time differences in hours
# [1] 1 2 3
#
# compare DST handling to durations
boundary <- as.POSIXct("2009-03-08 01:59:59")
# "2009-03-08 01:59:59 CST"
boundary + days(1) # period
# "2009-03-09 01:59:59 CDT" (clock time advances by a day)
boundary + edays(1) # duration
# "2009-03-09 02:59:59 CDT" (clock time corresponding to 86400 seconds later)}
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