| diff_tz {ds4psy} | R Documentation |
Get the time zone difference between two times.
Description
diff_tz computes the time difference
between two times t1 and t2
that is exclusively due to both times being in
different time zones.
Usage
diff_tz(t1, t2, in_min = FALSE)
Arguments
t1 |
First time (required, as "POSIXt" time point/moment). |
t2 |
Second time (required, as "POSIXt" time point/moment). |
in_min |
Return time-zone based time
difference in minutes (Boolean)?
Default: |
Details
diff_tz ignores all differences in nominal times,
but allows adjusting time-based computations
for time shifts that are due to time zone differences
(e.g., different locations, or
changes to/from daylight saving time, DST),
rather than differences in actual times.
Internally, diff_tz determines and contrasts the POSIX
conversion specifications "
(in numeric form).
If the lengths of t1 and t2 differ,
the shorter vector is recycled to the length of the longer one.
Value
A character (in "HH:MM" format) or numeric vector (number of minutes).
See Also
days_in_month for the number of days in given months;
is_leap_year to check for leap years.
Other date and time functions:
change_time(),
change_tz(),
cur_date(),
cur_time(),
days_in_month(),
diff_dates(),
diff_times(),
is_leap_year(),
what_date(),
what_month(),
what_time(),
what_wday(),
what_week(),
what_year(),
zodiac()
Examples
# Time zones differences:
tm <- "2020-01-01 01:00:00" # nominal time
t1 <- as.POSIXct(tm, tz = "Pacific/Auckland")
t2 <- as.POSIXct(tm, tz = "Europe/Berlin")
t3 <- as.POSIXct(tm, tz = "Pacific/Honolulu")
# as character (in "HH:MM"):
diff_tz(t1, t2)
diff_tz(t2, t3)
diff_tz(t1, t3)
# as numeric (in minutes):
diff_tz(t1, t3, in_min = TRUE)
# Compare local times (POSIXlt):
t4 <- as.POSIXlt(Sys.time(), tz = "Pacific/Auckland")
t5 <- as.POSIXlt(Sys.time(), tz = "Europe/Berlin")
diff_tz(t4, t5)
diff_tz(t4, t5, in_min = TRUE)
# DSL shift: Spring ahead (on 2020-03-29: 02:00:00 > 03:00:00):
s6 <- "2020-03-29 01:00:00 CET" # before DSL switch
s7 <- "2020-03-29 03:00:00 CEST" # after DSL switch
t6 <- as.POSIXct(s6, tz = "Europe/Berlin") # CET
t7 <- as.POSIXct(s7, tz = "Europe/Berlin") # CEST
diff_tz(t6, t7) # 1 hour forward
diff_tz(t6, t7, in_min = TRUE)