The Locale class

(PHP 5 >= 5.3.0, PHP 7, PHP 8, PECL intl >= 1.0.0)

Introduction

A "Locale" is an identifier used to get language, culture, or regionally-specific behavior from an API. PHP locales are organized and identified the same way that the CLDR locales used by ICU (and many vendors of Unix-like operating systems, the Mac, Java, and so forth) use. Locales are identified using RFC 4646 language tags (which use hyphen, not underscore) in addition to the more traditional underscore-using identifiers. Unless otherwise noted the functions in this class are tolerant of both formats.

Examples of identifiers include:

en-US (English, United States)
zh-Hant-TW (Chinese, Traditional Script, Taiwan)
fr-CA, fr-FR (French for Canada and France respectively)

The Locale class (and related procedural functions) are used to interact with locale identifiers--to verify that an ID is well-formed, valid, etc. The extensions used by CLDR in UAX #35 (and inherited by ICU) are valid and used wherever they would be in ICU normally.

Locales cannot be instantiated as objects. All of the functions/methods provided are static.

The null or empty string obtains the "root" locale. The "root" locale is equivalent to "en_US_POSIX" in CLDR. Language tags (and thus locale identifiers) are case insensitive. There exists a canonicalization function to make case match the specification.

Class synopsis

class Locale {

/* Methods */

public static acceptFromHttp(string $header): string|false

public static canonicalize(string $locale): ?string

public static composeLocale(array $subtags): string|false

public static filterMatches(string $languageTag, string $locale, bool $canonicalize = false): ?bool

public static getAllVariants(string $locale): ?array

public static getDefault(): string

public static getDisplayLanguage(string $locale, ?string $displayLocale = null): string|false

public static getDisplayName(string $locale, ?string $displayLocale = null): string|false

public static getDisplayRegion(string $locale, ?string $displayLocale = null): string|false

public static getDisplayScript(string $locale, ?string $displayLocale = null): string|false

public static getDisplayVariant(string $locale, ?string $displayLocale = null): string|false

public static getKeywords(string $locale): array|false|null

public static getPrimaryLanguage(string $locale): ?string

public static getRegion(string $locale): ?string

public static getScript(string $locale): ?string

public static lookup(
    array $languageTag,
    string $locale,
    bool $canonicalize = false,
    ?string $defaultLocale = null
): ?string

public static parseLocale(string $locale): ?array

public static setDefault(string $locale): bool

}

Predefined Constants

Locale::DEFAULT_LOCALE (null): Used as locale parameter with the methods of the various locale affected classes, such as NumberFormatter. This constant would make the methods to use default locale.

These constants describe the choice of the locale for the getLocale method of different classes.

Locale::ACTUAL_LOCALE (string): This is locale the data actually comes from.
Locale::VALID_LOCALE (string): This is the most specific locale supported by ICU.

These constants define how the Locales are parsed or composed. They should be used as keys in the argument array to locale_compose() and are returned from locale_parse() as keys of the returned associative array.