### ** Examples
x <- ymd_hms("2009-08-07 00:00:01", tz = "America/New_York")
force_tz(x, "UTC")
[1] "2009-08-07 00:00:01 UTC"
force_tz(x, "Europe/Amsterdam")
[1] "2009-08-07 00:00:01 CEST"
## DST skip:
y <- ymd_hms("2010-03-14 02:05:05 UTC")
force_tz(y, "America/New_York", roll=FALSE)
force_tz(y, "America/New_York", roll=TRUE)
[1] "2010-03-14 03:00:00 EDT"
## Heterogeneous time-zones:
x <- ymd_hms(c("2009-08-07 00:00:01", "2009-08-07 01:02:03"))
force_tzs(x, tzones = c("America/New_York", "Europe/Amsterdam"))
[1] "2009-08-07 04:00:01 UTC" "2009-08-06 23:02:03 UTC"
force_tzs(x, tzones = c("America/New_York", "Europe/Amsterdam"), tzone_out = "America/New_York")
[1] "2009-08-07 00:00:01 EDT" "2009-08-06 19:02:03 EDT"
x <- ymd_hms("2009-08-07 00:00:01")
force_tzs(x, tzones = c("America/New_York", "Europe/Amsterdam"))
[1] "2009-08-07 04:00:01 UTC" "2009-08-06 22:00:01 UTC"