| layout | title | permalink |
|---|---|---|
tutorial |
Dealing with Time Zones & Daylight Savings |
/time_zones/ |
To change the time zone for a date/time we can use the with_tz() function which will also update the clock time to align with the updated time zone:
library(lubridate)
time <- now()
time
## [1] "2015-09-26 10:30:32 EDT"
with_tz(time, tzone = "MST")
## [1] "2015-09-26 07:30:32 MST"If the time zone is incorrect or for some reason you need to change the time zone without changing the clock time you can force it with force_tz():
time
## [1] "2015-09-26 10:30:32 EDT"
force_tz(time, tzone = "MST")
## [1] "2015-09-26 10:30:32 MST"We can also easily work with daylight savings times to eliminate impacts on date/time calculations:
# most recent daylight savings time
ds <- ymd_hms("2015-03-08 01:59:59", tz = "US/Eastern")
# if we add a duration of 1 sec we gain an extra hour
ds + dseconds(1)
## [1] "2015-03-08 03:00:00 EDT"
# add a duration of 2 hours will reflect actual daylight savings clock time
# that occured 2 hours after 01:59:59 on 2015-03-08
ds + dhours(2)
## [1] "2015-03-08 04:59:59 EDT"
# add a period of two hours will reflect clock time that normally occurs after
# 01:59:59 and is not influenced by daylight savings time.
ds + hours(2)
## [1] "2015-03-08 03:59:59 EDT"