Unicode CLDR: The Database Behind Every Localized App

language[-script][-region][-variant][-extension]

Examples:
en           English (no region specified)
en-US        English, United States
en-GB        English, United Kingdom
zh-Hans      Chinese, Simplified script
zh-Hant-TW   Chinese, Traditional script, Taiwan
fr-CH        French, Switzerland
pt-BR        Portuguese, Brazil
sr-Cyrl      Serbian, Cyrillic script
sr-Latn      Serbian, Latin script

en-US-u-nu-latn    English, US, using Latin numerals (explicit)
ar-u-nu-arab       Arabic, using Arabic-Indic numerals
zh-u-co-pinyin     Chinese, using Pinyin collation order
en-u-ca-buddhist   English, using Buddhist calendar

# Python Babel uses BCP 47 locale identifiers
from babel import Locale

loc = Locale.parse('fr_CH', sep='_')  # Babel uses underscore
print(loc.get_display_name('en'))     # 'French (Switzerland)'
print(loc.number_symbols['decimal'])  # '.' (Swiss French uses period)
print(loc.number_symbols['group'])    # '\u2019' (apostrophe as thousands sep)

from babel.numbers import format_number, format_currency, format_percent

number = 1234567.89

# Basic number formatting
print(format_number(number, locale='en_US'))  # 1,234,567.89
print(format_number(number, locale='de_DE'))  # 1.234.567,89
print(format_number(number, locale='fr_FR'))  # 1 234 567,89
print(format_number(number, locale='hi_IN'))  # 12,34,567.89

# Currency formatting
print(format_currency(1234.56, 'USD', locale='en_US'))   # $1,234.56
print(format_currency(1234.56, 'USD', locale='de_DE'))   # 1.234,56 $
print(format_currency(1234.56, 'EUR', locale='fr_FR'))   # 1 234,56 €
print(format_currency(1234.56, 'JPY', locale='ja_JP'))   # ¥1,235 (no decimals)

# Percent
print(format_percent(0.756, locale='en_US'))   # 75.6%
print(format_percent(0.756, locale='tr_TR'))   # %75,6 (% before number in Turkish)

# Parsing numbers from locale-formatted strings
from babel.numbers import parse_number
print(parse_number('1.234.567,89', locale='de_DE'))  # 1234567.89

const number = 1234567.89;

// Basic formatting
new Intl.NumberFormat('en-US').format(number);   // '1,234,567.89'
new Intl.NumberFormat('de-DE').format(number);   // '1.234.567,89'
new Intl.NumberFormat('fr-FR').format(number);   // '1 234 567,89'
new Intl.NumberFormat('hi-IN').format(number);   // '12,34,567.89'
new Intl.NumberFormat('ar-SA').format(number);   // '١٬٢٣٤٬٥٦٧٫٨٩'

// Currency
new Intl.NumberFormat('en-US', {
    style: 'currency',
    currency: 'USD'
}).format(1234.56);  // '$1,234.56'

new Intl.NumberFormat('ja-JP', {
    style: 'currency',
    currency: 'JPY'
}).format(1234.56);  // '¥1,235'

// Compact notation
new Intl.NumberFormat('en-US', { notation: 'compact' }).format(1234567);  // '1.2M'
new Intl.NumberFormat('ko-KR', { notation: 'compact' }).format(1234567);  // '123만' (10,000 units)

// Percent
new Intl.NumberFormat('en-US', { style: 'percent' }).format(0.756);  // '75.6%'
new Intl.NumberFormat('tr-TR', { style: 'percent' }).format(0.756);  // '%75,6'

from babel.dates import format_date, format_datetime, format_time
from datetime import date, datetime

d = date(2024, 3, 25)
dt = datetime(2024, 3, 25, 15, 30, 0)

# Date formats
print(format_date(d, format='long', locale='en_US'))   # March 25, 2024
print(format_date(d, format='long', locale='de_DE'))   # 25. März 2024
print(format_date(d, format='long', locale='ja_JP'))   # 2024年3月25日
print(format_date(d, format='long', locale='ar_SA'))   # ٢٥ مارس ٢٠٢٤

# Time formats (note: 12h vs 24h varies by locale)
print(format_time(dt, format='short', locale='en_US'))  # 3:30 PM
print(format_time(dt, format='short', locale='de_DE'))  # 15:30
print(format_time(dt, format='short', locale='zh_CN'))  # 下午3:30

# Full datetime
print(format_datetime(dt, format='full', locale='en_US'))
# Monday, March 25, 2024 at 3:30:00 PM Coordinated Universal Time

print(format_datetime(dt, format='full', locale='fr_FR'))
# lundi 25 mars 2024 à 15:30:00 Temps universel coordonné

const date = new Date(2024, 2, 25, 15, 30, 0);  // March 25, 2024

// Date
new Intl.DateTimeFormat('en-US', { dateStyle: 'long' }).format(date);
// 'March 25, 2024'

new Intl.DateTimeFormat('de-DE', { dateStyle: 'long' }).format(date);
// '25. März 2024'

new Intl.DateTimeFormat('ja-JP', { dateStyle: 'long' }).format(date);
// '2024年3月25日'

// Time
new Intl.DateTimeFormat('en-US', { timeStyle: 'short' }).format(date);
// '3:30 PM'

new Intl.DateTimeFormat('de-DE', { timeStyle: 'short' }).format(date);
// '15:30'

// Relative time
const rtf = new Intl.RelativeTimeFormat('en', { numeric: 'auto' });
rtf.format(-1, 'day');   // 'yesterday'
rtf.format(2, 'week');   // 'in 2 weeks'

const rtfFr = new Intl.RelativeTimeFormat('fr', { numeric: 'auto' });
rtfFr.format(-1, 'day'); // 'hier' (yesterday in French)
rtfFr.format(2, 'week'); // 'dans 2 semaines'

from babel.plural import get_plural_tag
from babel.core import Locale

# Get plural form for a number
def get_plural_form(n, locale_str):
    loc = Locale.parse(locale_str)
    tag = loc.plural_form(n)
    return tag

print(get_plural_form(1, 'en_US'))   # one
print(get_plural_form(2, 'en_US'))   # other
print(get_plural_form(0, 'fr_FR'))   # one (French treats 0 as singular)
print(get_plural_form(1, 'ru_RU'))   # one
print(get_plural_form(2, 'ru_RU'))   # few
print(get_plural_form(5, 'ru_RU'))   # many
print(get_plural_form(1, 'ar'))      # one
print(get_plural_form(2, 'ar'))      # two
print(get_plural_form(5, 'ar'))      # few
print(get_plural_form(11, 'ar'))     # many

// English: one vs other
const en = new Intl.PluralRules('en');
[0, 1, 2, 5, 10].map(n => `${n}: ${en.select(n)}`);
// ['0: other', '1: one', '2: other', '5: other', '10: other']

// Russian: one, few, many, other
const ru = new Intl.PluralRules('ru');
[1, 2, 5, 11, 21].map(n => `${n}: ${ru.select(n)}`);
// ['1: one', '2: few', '5: many', '11: many', '21: one']

// Practical use: select the correct string
function pluralize(n, forms, locale) {
    const plural = new Intl.PluralRules(locale);
    const form = plural.select(n);
    return `${n} ${forms[form] || forms.other}`;
}

// English
pluralize(1, { one: 'file', other: 'files' }, 'en');   // '1 file'
pluralize(5, { one: 'file', other: 'files' }, 'en');   // '5 files'

// Russian (conceptual — real app would use i18n library)
pluralize(1, { one: 'файл', few: 'файла', many: 'файлов', other: 'файлов' }, 'ru');
// '1 файл'

# Wrong: byte-order sort
names = ['Ångström', 'Åse', 'Bitte', 'ändern', 'Über']
print(sorted(names))
# ['Bitte', 'Über', 'Ångström', 'Åse', 'ändern']  — completely wrong for German/Swedish

# Correct: ICU collation via PyICU
# pip install PyICU
import icu

# German collation
german_coll = icu.Collator.createInstance(icu.Locale('de_DE'))
print(sorted(names, key=german_coll.getSortKey))
# ['ändern', 'Ångström', 'Åse', 'Bitte', 'Über']  — ä/Å near a, Ü near u

# Swedish collation (ä and ö sort after z!)
swedish_coll = icu.Collator.createInstance(icu.Locale('sv_SE'))
print(sorted(names, key=swedish_coll.getSortKey))
# ['Bitte', 'Über', 'ändern', 'Ångström', 'Åse']  — ä/å after z in Swedish

// JavaScript: Intl.Collator
const names = ['Ångström', 'Åse', 'Bitte', 'ändern', 'Über'];

// German collation
const german = new Intl.Collator('de-DE');
console.log(names.sort((a, b) => german.compare(a, b)));
// ['ändern', 'Ångström', 'Åse', 'Bitte', 'Über']

// Swedish collation
const swedish = new Intl.Collator('sv-SE');
console.log(names.sort((a, b) => swedish.compare(a, b)));
// ['Bitte', 'Über', 'ändern', 'Ångström', 'Åse']

// Chinese by Pinyin
const chineseWords = ['中文', '北京', '汉字', '语言'];
const pinyin = new Intl.Collator('zh-Hans-u-co-pinyin');
console.log(chineseWords.sort((a, b) => pinyin.compare(a, b)));

const items = ['apples', 'oranges', 'bananas'];

new Intl.ListFormat('en', { type: 'conjunction' }).format(items);
// 'apples, oranges, and bananas'

new Intl.ListFormat('fr', { type: 'conjunction' }).format(items);
// 'apples, oranges et bananas' (no Oxford comma)

new Intl.ListFormat('de', { type: 'conjunction' }).format(items);
// 'apples, oranges und bananas'

new Intl.ListFormat('zh', { type: 'conjunction' }).format(items);
// 'apples、oranges和bananas' (uses Chinese enumeration comma 、)

from babel.lists import format_list

print(format_list(['apples', 'oranges', 'bananas'], locale='en_US'))
# 'apples, oranges, and bananas'

print(format_list(['apples', 'oranges', 'bananas'], locale='fr_FR'))
# 'apples, oranges et bananas'

// Names of languages in different display languages
new Intl.DisplayNames(['en'], { type: 'language' }).of('de');  // 'German'
new Intl.DisplayNames(['de'], { type: 'language' }).of('de');  // 'Deutsch'
new Intl.DisplayNames(['ja'], { type: 'language' }).of('de');  // 'ドイツ語'
new Intl.DisplayNames(['ko'], { type: 'language' }).of('de');  // '독일어'

// Region names
new Intl.DisplayNames(['en'], { type: 'region' }).of('JP');  // 'Japan'
new Intl.DisplayNames(['ja'], { type: 'region' }).of('JP');  // '日本'
new Intl.DisplayNames(['ar'], { type: 'region' }).of('JP');  // 'اليابان'

// Currency names
new Intl.DisplayNames(['en'], { type: 'currency' }).of('JPY');  // 'Japanese Yen'
new Intl.DisplayNames(['ja'], { type: 'currency' }).of('JPY');  // '日本円'

// Script names
new Intl.DisplayNames(['en'], { type: 'script' }).of('Hang');  // 'Hangul'
new Intl.DisplayNames(['ko'], { type: 'script' }).of('Hang');  // '한글'

# Django template usage
# {% load i18n %}
# {{ value|intcomma }}     → locale-aware thousands separator
# {{ value|floatformat:2}} → locale-aware decimal formatting

# Python code
from django.utils.formats import number_format, date_format
from django.utils import translation

with translation.override('de'):
    print(number_format(1234567.89))         # '1.234.567,89'
    print(date_format(date(2024, 3, 25), 'D, j N Y'))
    # 'Mo., 25. März 2024'

with translation.override('ja'):
    print(date_format(date(2024, 3, 25), 'Y年n月j日'))
    # '2024年3月25日'

# Access CLDR JSON data directly
# npm install @unicode/cldr-core (Node.js)
# or pip install cldr-json-fetch (Python)

import json

# Load CLDR number data for German
# (assuming cldr-json data directory is available)
with open('cldr-numbers-modern/main/de/numbers.json') as f:
    de_numbers = json.load(f)

symbols = de_numbers['main']['de']['numbers']['symbols-numberSystem-latn']
print(symbols['decimal'])   # ','
print(symbols['group'])     # '.'

patterns = de_numbers['main']['de']['numbers']['decimalFormats-numberSystem-latn']
print(patterns['standard'])  # '#,##0.###'

// Comprehensive i18n setup (React/Node.js example pattern)
function formatForLocale(locale) {
    const number = 1234567.89;
    const date = new Date(2024, 2, 25);
    const amount = 1234.56;
    const items = ['apple', 'banana', 'cherry'];

    return {
        number: new Intl.NumberFormat(locale).format(number),
        currency: new Intl.NumberFormat(locale, {
            style: 'currency',
            currency: 'USD'
        }).format(amount),
        date: new Intl.DateTimeFormat(locale, {
            dateStyle: 'long'
        }).format(date),
        list: new Intl.ListFormat(locale, {
            type: 'conjunction'
        }).format(items),
        plural: (() => {
            const pr = new Intl.PluralRules(locale);
            const n = 5;
            const forms = {
                en: { one: 'file', other: 'files' },
                de: { one: 'Datei', other: 'Dateien' },
                ru: { one: 'файл', few: 'файла', many: 'файлов', other: 'файлов' }
            };
            const form = pr.select(n);
            const lang = new Intl.Locale(locale).language;
            return `${n} ${(forms[lang] || forms.en)[form]}`;
        })()
    };
}

console.log(formatForLocale('en-US'));
// { number: '1,234,567.89', currency: '$1,234.56',
//   date: 'March 25, 2024', list: 'apple, banana, and cherry',
//   plural: '5 files' }

console.log(formatForLocale('de-DE'));
// { number: '1.234.567,89', currency: '1.234,56 $',
//   date: '25. März 2024', list: 'apple, banana und cherry',
//   plural: '5 Dateien' }