Resolve a time zone

Finds the time zone an object is displayed in, falling back to default if the object doesn't name one (it lacks a "tzone" attribute, or that attribute is NA, empty, or "").

Usage

resolve_tz(x = NULL, default = Sys.timezone(), call = caller_env())

Arguments

x

An object, usually a base::POSIXct or base::POSIXlt vector, whose "tzone" attribute should be used. The default, NULL, has no time zone, so resolve_tz() returns default.

default

(character(1)) The time zone to use if x doesn't name one. Defaults to your local time zone, as reported by Sys.timezone(). As in to_dttm(), "" is replaced by the name of your local time zone.

call

(environment) The execution environment to mention as the source of error messages.

Value

The name of a time zone from OlsonNames() as a character string, or an error condition with classes <stbl-error-bad_tz>, <stbl-error>, <stbl-condition>, <rlang_error>, <error>, <condition> when the time zone cannot be determined or is not a value from OlsonNames().

See also

Other datetime functions: locale_datetime_formats(), specify_dttm(), stabilize_dttm(), stabilize_dttm_scalar(), to(), to_dttm(), to_dttm_scalar()

Examples

resolve_tz()
#> [1] "UTC"
resolve_tz(as.POSIXct("2024-01-01 12:00:00", tz = "America/Chicago"))
#> [1] "America/Chicago"
resolve_tz(Sys.time(), default = "UTC")
#> [1] "UTC"

# Keep the time zone of the input, using your local time zone if it has none.
x <- as.POSIXct("2024-01-01 12:00:00", tz = "Asia/Tokyo")
to_dttm(x, tz = resolve_tz(x))
#> [1] "2024-01-01 12:00:00 JST"
try(resolve_tz(default = "this is not a timezone"))
#> Error in eval(expr, envir) : 
#>   `default` must be "" or a value from `OlsonNames()`.
#> ✖ "this is not a timezone" is not a recognized time zone.