Struct ZonedDateTimeFormatter

pub struct ZonedDateTimeFormatter(/* private fields */);

ZonedDateTimeFormatter is a formatter capable of formatting date/times with time zones from any calendar, selected at runtime. For the difference between this and TypedZonedDateTimeFormatter, please read the crate root docs.

This is equivalently the composition of DateTimeFormatter and TimeZoneFormatter.

ZonedDateTimeFormatter uses data from the [data provider]s, the selected DataLocale, and the provided pattern to collect all data necessary to format a datetime with time zones into that locale.

The various pattern symbols specified in UTS-35 require different sets of data for formatting. As such, TimeZoneFormatter will pull in only the resources it needs to format that pattern that is derived from the provided DateTimeFormatterOptions.

For that reason, one should think of the process of formatting a zoned datetime in two steps: first, a computationally heavy construction of ZonedDateTimeFormatter, and then fast formatting of the data using the instance. 📏 This item has a stack size of 6248 bytes on the stable toolchain at release date.

Examples

Using a GMT time zone:

use icu::calendar::DateTime;
use icu::datetime::{options::length, ZonedDateTimeFormatter};
use icu::locid::locale;
use icu::timezone::CustomTimeZone;
use writeable::assert_writeable_eq;

let options = length::Bag::from_date_time_style(
    length::Date::Medium,
    length::Time::Long,
);
let zdtf = ZonedDateTimeFormatter::try_new(
    &locale!("en").into(),
    options.into(),
    Default::default(),
)
.expect("Failed to create ZonedDateTimeFormatter instance.");

let datetime = DateTime::try_new_iso_datetime(2020, 9, 1, 12, 34, 28)
    .expect("Failed to construct DateTime.");
let any_datetime = datetime.to_any();

let time_zone = CustomTimeZone::utc();

assert_writeable_eq!(
    zdtf.format(&any_datetime, &time_zone)
        .expect("Calendars should match"),
    "Sep 1, 2020, 12:34:28 PM GMT"
);

Using a non-GMT time zone, specified by id:

use icu::calendar::DateTime;
use icu::datetime::{options::length, ZonedDateTimeFormatter};
use icu::locid::locale;
use icu::timezone::{CustomTimeZone, GmtOffset, MetazoneCalculator, ZoneVariant};
use tinystr::TinyAsciiStr;
use writeable::assert_writeable_eq;

let options = length::Bag::from_date_time_style(
    length::Date::Medium,
    length::Time::Full,
);
let zdtf = ZonedDateTimeFormatter::try_new(
    &locale!("en").into(),
    options.into(),
    Default::default(),
)
.expect("Failed to create ZonedDateTimeFormatter instance.");

// Create a DateTime at September 1, 2020 at 12:34:28 PM
let datetime = DateTime::try_new_iso_datetime(2020, 9, 1, 12, 34, 28)
    .expect("Failed to construct DateTime.");
let any_datetime = datetime.to_any();

// Create a time zone for America/Chicago at GMT-6:
let mut time_zone = CustomTimeZone::new_empty();
time_zone.gmt_offset = "-06:00".parse::<GmtOffset>().ok();
time_zone.time_zone_id = "uschi".parse::<TinyAsciiStr<8>>().ok().map(Into::into);
time_zone.zone_variant = Some(ZoneVariant::daylight());

// Compute the metazone during `datetime` (September 1, 2020 at 12:34:28 PM):
let mzc = MetazoneCalculator::new();
time_zone.maybe_calculate_metazone(&mzc, &datetime);

assert_writeable_eq!(
    zdtf
      .format(&any_datetime, &time_zone)
      .expect("Calendars should match"),
    "Sep 1, 2020, 12:34:28 PM Central Daylight Time");

Implementations

impl ZonedDateTimeFormatter

pub fn try_new( locale: &DataLocale, date_time_format_options: DateTimeFormatterOptions, time_zone_format_options: TimeZoneFormatterOptions, ) -> Result<Self, DateTimeError>

Constructor that takes a selected DataLocale and a list of DateTimeFormatterOptions and uses compiled data. It collects all data necessary to format zoned datetime values into the given locale.

This method will pick the calendar off of the locale; and if unspecified or unknown will fall back to the default calendar for the locale. See AnyCalendarKind for a list of supported calendars.

✨ Enabled with the compiled_data Cargo feature.

📚 Help choosing a constructor

Examples

use icu::calendar::DateTime;
use icu::datetime::options::length;
use icu::datetime::time_zone::TimeZoneFormatterOptions;
use icu::datetime::ZonedDateTimeFormatter;
use icu::locid::locale;
use icu::timezone::CustomTimeZone;
use std::str::FromStr;
use writeable::assert_writeable_eq;

let options = length::Bag::from_date_time_style(
    length::Date::Medium,
    length::Time::Long,
);
let locale = locale!("en-u-ca-gregory").into();

let zdtf = ZonedDateTimeFormatter::try_new(
    &locale,
    options.into(),
    TimeZoneFormatterOptions::default(),
)
.expect("Construction should succeed");

let datetime =
    DateTime::try_new_iso_datetime(2021, 04, 08, 16, 12, 37).unwrap();
let time_zone = CustomTimeZone::from_str("-07:00").unwrap();
let any_datetime = datetime.to_any();

assert_writeable_eq!(
    zdtf.format(&any_datetime, &time_zone).unwrap(),
    "Apr 8, 2021, 4:12:37 PM GMT-07:00"
);

pub fn try_new_unstable<P>( provider: &P, locale: &DataLocale, date_time_format_options: DateTimeFormatterOptions, time_zone_format_options: TimeZoneFormatterOptions, ) -> Result<Self, DateTimeError>

where P: DataProvider<TimeSymbolsV1Marker> + DataProvider<TimeLengthsV1Marker> + DataProvider<WeekDataV1Marker> + DataProvider<TimeZoneFormatsV1Marker> + DataProvider<ExemplarCitiesV1Marker> + DataProvider<MetazoneGenericNamesLongV1Marker> + DataProvider<MetazoneGenericNamesShortV1Marker> + DataProvider<MetazoneSpecificNamesLongV1Marker> + DataProvider<MetazoneSpecificNamesShortV1Marker> + DataProvider<OrdinalV1Marker> + DataProvider<DecimalSymbolsV1Marker> + DataProvider<BuddhistDateLengthsV1Marker> + DataProvider<BuddhistDateSymbolsV1Marker> + DataProvider<ChineseCacheV1Marker> + DataProvider<ChineseDateLengthsV1Marker> + DataProvider<ChineseDateSymbolsV1Marker> + DataProvider<CopticDateLengthsV1Marker> + DataProvider<CopticDateSymbolsV1Marker> + DataProvider<DangiCacheV1Marker> + DataProvider<DangiDateLengthsV1Marker> + DataProvider<DangiDateSymbolsV1Marker> + DataProvider<EthiopianDateLengthsV1Marker> + DataProvider<EthiopianDateSymbolsV1Marker> + DataProvider<GregorianDateLengthsV1Marker> + DataProvider<GregorianDateSymbolsV1Marker> + DataProvider<HebrewDateLengthsV1Marker> + DataProvider<HebrewDateSymbolsV1Marker> + DataProvider<IndianDateLengthsV1Marker> + DataProvider<IndianDateSymbolsV1Marker> + DataProvider<IslamicDateLengthsV1Marker> + DataProvider<IslamicDateSymbolsV1Marker> + DataProvider<IslamicObservationalCacheV1Marker> + DataProvider<IslamicUmmAlQuraCacheV1Marker> + DataProvider<JapaneseDateLengthsV1Marker> + DataProvider<JapaneseDateSymbolsV1Marker> + DataProvider<JapaneseErasV1Marker> + DataProvider<JapaneseExtendedDateLengthsV1Marker> + DataProvider<JapaneseExtendedDateSymbolsV1Marker> + DataProvider<JapaneseExtendedErasV1Marker> + DataProvider<PersianDateLengthsV1Marker> + DataProvider<PersianDateSymbolsV1Marker> + DataProvider<RocDateLengthsV1Marker> + DataProvider<RocDateSymbolsV1Marker> + ?Sized,

A version of Self::try_new that uses custom data provided by a DataProvider.

📚 Help choosing a constructor

⚠️ The bounds on provider may change over time, including in SemVer minor releases.

pub fn try_new_with_any_provider( provider: &impl AnyProvider, locale: &DataLocale, options: DateTimeFormatterOptions, time_zone_format_options: TimeZoneFormatterOptions, ) -> Result<Self, DateTimeError>

A version of Self::try_new that uses custom data provided by an AnyProvider.

📚 Help choosing a constructor

pub fn try_new_with_buffer_provider( provider: &impl BufferProvider, locale: &DataLocale, options: DateTimeFormatterOptions, time_zone_format_options: TimeZoneFormatterOptions, ) -> Result<Self, DateTimeError>

A version of Self::try_new that uses custom data provided by a BufferProvider.

✨ Enabled with the serde feature.

📚 Help choosing a constructor

pub fn format<'l>( &'l self, date: &impl DateTimeInput<Calendar = AnyCalendar>, time_zone: &impl TimeZoneInput, ) -> Result<FormattedZonedDateTime<'l>, DateTimeError>

Takes a DateTimeInput and a TimeZoneInput and returns an instance of a FormattedZonedDateTime that contains all information necessary to display a formatted date and operate on it.

This function will fail if the date passed in uses a different calendar than that of the AnyCalendar. Please convert dates before passing them in if necessary. This function will automatically convert and format dates that are associated with the ISO calendar.

pub fn format_to_string( &self, date: &impl DateTimeInput<Calendar = AnyCalendar>, time_zone: &impl TimeZoneInput, ) -> Result<String, DateTimeError>

Takes a DateTimeInput and a TimeZoneInput and returns it formatted as a string.

This function will fail if the date passed in uses a different calendar than that of the AnyCalendar. Please convert dates before passing them in if necessary. This function will automatically convert and format dates that are associated with the ISO calendar.

Trait Implementations

impl Debug for ZonedDateTimeFormatter

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.