Localize Playground

🇺🇸 English ▾

List

Locale

Formatted output

red, green, and blue

Localize.List.to_string(
  ["red", "green", "blue"],
  locale: "en", list_style: :standard
)

Items

Items (one per line) Each line becomes one element in the list.

Pattern for this locale × style

CLDR list patterns use four slots — start, middle, end, and the special two-item pattern for lists of exactly two. `0` and `1` are substituted with list elements.

Start: [0, ", ", 1]
Middle: [0, ", ", 1]
End: [0, ", and ", 1]
Two (special): [0, " and ", 1]

Examples

CLDR format pattern reference

Date/time patterns use unquoted letters as format codes. Repeat a letter to change width; wrap literal text in single quotes. See CLDR docs for the full spec.

Year

Pattern	Meaning	Example
`y`	Calendar year. Truncates to min digits.	`2026 · 26`
`yy`	2-digit year.	`26`
`yyyy`	4-digit year (zero-padded).	`2026`
`Y`	Week-based year (ISO).	`2026`
`u`	Extended year.	`2026`
`U`	Cyclic year name (e.g., Chinese zodiac).	`丙午`
`r`	Related Gregorian year.	`2026`

Quarter

Pattern	Meaning	Example
`Q`	Quarter number.	`2`
`QQ`	Quarter number, 2-digit.	`02`
`QQQ`	Abbreviated quarter name.	`Q2`
`QQQQ`	Wide quarter name.	`2nd quarter`
`q`	Stand-alone quarter (same but in isolation).	`2`

Month

Pattern	Meaning	Example
`M`	Month number.	`4`
`MM`	Month number, 2-digit.	`04`
`MMM`	Abbreviated month name.	`Apr`
`MMMM`	Wide month name.	`April`
`MMMMM`	Narrow month name.	`A`
`L`	Stand-alone month number.	`4`
`LLLL`	Stand-alone wide month name.	`April`

Week

Pattern	Meaning	Example
`w`	Week of year.	`15`
`ww`	Week of year, 2-digit.	`15`
`W`	Week of month.	`3`

Day

Pattern	Meaning	Example
`d`	Day of month.	`15`
`dd`	Day of month, 2-digit.	`15`
`D`	Day of year.	`105`
`F`	Day of week in month (e.g., 3rd Tuesday).	`3`
`g`	Modified Julian Day.	`2460785`

Weekday

Pattern	Meaning	Example
`E`	Abbreviated day name.	`Wed`
`EEEE`	Wide day name.	`Wednesday`
`EEEEE`	Narrow day name.	`W`
`e`	Local day of week (locale-dependent start).	`4`
`c`	Stand-alone day of week.	`4`
`cccc`	Stand-alone wide day name.	`Wednesday`

Period / AM-PM

Pattern	Meaning	Example
`a`	AM/PM marker.	`PM`
`aaaa`	Wide AM/PM marker.	`in the afternoon`
`b`	AM/PM + noon/midnight.	`noon`
`B`	Flexible day period.	`in the afternoon`

Hour

Pattern	Meaning	Example
`h`	Hour 1–12.	`6`
`hh`	Hour 1–12, 2-digit.	`06`
`H`	Hour 0–23.	`18`
`HH`	Hour 0–23, 2-digit.	`18`
`K`	Hour 0–11.	`6`
`k`	Hour 1–24.	`18`
`j`	Locale's preferred hour field (use in skeletons).	`6 PM`
`J`	Locale's preferred hour without day period.	`18`

Minute / Second

Pattern	Meaning	Example
`m`	Minute.	`9`
`mm`	Minute, 2-digit.	`09`
`s`	Second.	`7`
`ss`	Second, 2-digit.	`07`
`S`	Fractional second.	`1`
`SSS`	Milliseconds.	`123`
`A`	Milliseconds of day.	`65430000`

Time zone — specific

Pattern	Meaning	Example
`z`	Short specific non-location.	`PT`
`zzzz`	Long specific non-location.	`Pacific Time`
`Z`	ISO 8601 basic (-0800).	`-0800`
`ZZZZ`	Long localized GMT.	`GMT-08:00`
`ZZZZZ`	ISO 8601 extended (-08:00) or 'Z'.	`-08:00`
`O`	Short localized GMT.	`GMT-8`
`OOOO`	Long localized GMT.	`GMT-08:00`

Time zone — generic & location

Pattern	Meaning	Example
`v`	Short generic non-location.	`PT`
`vvvv`	Long generic non-location.	`Pacific Time`
`V`	Short time zone ID.	`uslax`
`VV`	Long time zone ID.	`America/Los_Angeles`
`VVV`	Exemplar city.	`Los Angeles`
`VVVV`	Generic location format.	`Los Angeles Time`
`X`	ISO 8601 with Z for UTC (-08, -0800, Z).	`-08`
`x`	ISO 8601 numeric (-0800, no Z).	`-0800`

Era

Pattern	Meaning	Example
`G`	Era abbreviation.	`AD`
`GGGG`	Era wide.	`Anno Domini`
`GGGGG`	Era narrow.	`A`

Literals & escaping

Pattern	Meaning	Example
`'text'`	Literal text inside single quotes.	`'at' → at`
`''`	Escaped single quote.	`it's → it''s`
`:`	Time separator placeholder (locale-adjusted).	`:`

MessageFormat 2 syntax reference

MF2 is a two-level grammar: messages can be plain text (a simple message) or a pattern wrapped in {{}} with optional declarations and matchers. See the official spec for the full grammar.

Simple vs complex messages

Syntax	Meaning	Example output
`Hello, world!`	Simple message — plain text is a valid message.	`Hello, world!`
`{{Hello, {$name}!}}`	Quoted pattern — required when the message has declarations, matchers, or starts with { or .	`Hello, Aoife!`
`.local $x = {1} {{Value: {$x}}}`	Complex message — declarations followed by a quoted pattern.	`Value: 1`

Placeholders

Syntax	Meaning	Example output
`{$name}`	Variable reference — binds to the bindings map/keyword.	`Aoife`
`{\|literal text\|}`	Literal — explicit quoted value. Rare in practice.	`literal text`
`{42}`	Number literal.	`42`
`{$x :number}`	Annotated variable — applies a function to the value.	`3`
`{$x :number minimumFractionDigits=2}`	Annotated with options.	`3.00`

Built-in functions

Syntax	Meaning	Example output
`:string`	Selects/formats a string value (default for strings).
`:number`	Formats a number. Options: minimumFractionDigits, maximumFractionDigits, minimumIntegerDigits, useGrouping, signDisplay, notation.	`1,234.50`
`:integer`	Formats an integer.	`1,234`
`:currency`	Formats as currency. Options: currency=ISO, currencyDisplay=code\|symbol\|name\|narrowSymbol.	`$1,234.56`
`:date`	Formats a date. Options: dateStyle=short\|medium\|long\|full.	`Apr 15, 2026`
`:time`	Formats a time. Options: timeStyle=short\|medium\|long\|full.	`3:04 PM`
`:datetime`	Formats a date and time.	`Apr 15, 2026, 3:04 PM`

Declarations

Syntax	Meaning	Example output
`.local $x = {expr}`	Bind a local variable to an expression (placeholder).
`.input {$x :number}`	Re-annotate an incoming binding with a function/options.

Selection / matchers

Syntax	Meaning	Example output
`.match $count`	Select a variant based on one or more selectors.
`0 {{No items.}}`	Literal variant — matched when $count == 0.	`No items.`
`one {{1 item}}`	Plural keyword variant (:number selector).	`1 item`
`* {{N items.}}`	Default/wildcard variant. Required.	`N items.`
`.match $a $b hi hi {{both hi}} * * {{anything}}`	Multi-selector — one row per combination. Wildcards * act as catch-alls.

Markup

Syntax	Meaning	Example output
`{#link}Click here{/link}`	Open / close markup — the formatter can emit structured output (HTML, etc.).
`{#img src=\|photo.jpg\| /}`	Self-closing markup with options.

Escaping

Syntax	Meaning	Example output
`\{`	Literal open brace.	`{`
`\}`	Literal close brace.	`}`
`\\`	Literal backslash.	`\`
`\\|`	Literal pipe inside \|...\| literals.	`\|`

Common patterns

Syntax	Meaning	Example output
`.match {$count :number} one {{1 unread}} * {{{$count} unread}}`	Plural message using CLDR plural categories.	`3 unread`
`.match {$gender :string} feminine {{She}} masculine {{He}} * {{They}}`	Gender/string selection.	`They`
`{{Total: {$amount :currency currency=USD}}}`	Currency formatting with options.	`Total: $1,234.56`
`{{Today is {$d :date dateStyle=full}}}`	Long date.	`Today is Wednesday, April 15, 2026`

List

Formatted output

Items

List style

Pattern for this locale × style

Examples