seconds
Quickly create relative timespans.
Quickly create relative timespans.
Usage
seconds(x=1)Arguments
- x
- numeric value of the number of units to be contained in the period. With the exception of seconds(), x must be an integer.
Details
Quickly create period objects for easy date-time manipulation. The
units of the period created depend on the name of the function
called. For period objects, units do not have a fixed length until
they are added to a specific date time, contrast this with
durations. This makes periods useful for manipulations
with clock times because units expand or contract in length to
accomodate conventions such as leap years, leap seconds, and Daylight
Savings Time.
When paired with date-times, these functions allow date-times to be manipulated in a method similar to object oriented programming. Period objects can be added to Date, POSIXt, and Interval objects.
y, m, w, d are predefined period objects such that y = 1 year, m = 1 month, w = 1 week, d = 1 day.
Value
- a period object
See Also
Examples
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 + days(1) + hours(6) + minutes(30)
# "2009-08-04 06:30:00 CDT"
x + days(100) - hours(8)
# "2009-11-10 15:00:00 CST"
class(as.Date("2009-08-09") + days(1)) # retains Date class
# "Date"
as.Date("2009-08-09") + hours(12)
# "2009-08-09 12:00:00 UTC"
class(as.Date("2009-08-09") + hours(12))
# "POSIXt" "POSIXct"
# converts to POSIXt class to accomodate time units
years(1) - months(7)
# 1 year and -7 months
c(1:3) * hours(1)
# 1 hour 2 hours 3 hours
hours(1:3)
# 1 hour 2 hours 3 hours
#sequencing
y <- ymd(090101) # "2009-01-01 CST"
y + months(0:11)
# [1] "2009-01-01 CST" "2009-02-01 CST" "2009-03-01 CST" "2009-04-01 CDT"
# [5] "2009-05-01 CDT" "2009-06-01 CDT" "2009-07-01 CDT" "2009-08-01 CDT"
# [9] "2009-09-01 CDT" "2009-10-01 CDT" "2009-11-01 CDT" "2009-12-01 CST"
# end of month handling
ymd(20090131) + months(0:11)
# Undefined date. Defaulting to last previous real day.
# [1] "2009-01-31 CST" "2009-02-28 CST" "2009-03-31 CDT" "2009-04-30 CDT"
# [5] "2009-05-31 CDT" "2009-06-30 CDT" "2009-07-31 CDT" "2009-08-31 CDT"
# [9] "2009-09-30 CDT" "2009-10-31 CDT" "2009-11-30 CST" "2009-12-31 CST"
# 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)}