The NumberFormatter class

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

Introduzione

Programs store and operate on numbers using a locale-independent binary representation. When displaying or printing a number it is converted to a locale-specific string. For example, the number 12345.67 is "12,345.67" in the US, "12 345,67" in France and "12.345,67" in Germany.

By invoking the methods provided by the NumberFormatter class, you can format numbers, currencies, and percentages according to the specified or default locale. NumberFormatter is locale-sensitive so you need to create a new NumberFormatter for each locale. NumberFormatter methods format primitive-type numbers, such as double and output the number as a locale-specific string.

For currencies you can use currency format type to create a formatter that returns a string with the formatted number and the appropriate currency sign. Of course, the NumberFormatter class is unaware of exchange rates so, the number output is the same regardless of the specified currency. This means that the same number has different monetary values depending on the currency locale. If the number is 9988776.65 the results will be:

9 988 776,65 € in France
9.988.776,65 € in Germany
$9,988,776.65 in the United States

In order to format percentages, create a locale-specific formatter with percentage format type. With this formatter, a decimal fraction such as 0.75 is displayed as 75%.

For more complex formatting, like spelled-out numbers, the rule-based number formatters are used.

Sommario della classe

class NumberFormatter {

/* Costanti */

public const int PATTERN_DECIMAL;

public const int DECIMAL;

public const int CURRENCY;

public const int PERCENT;

public const int SCIENTIFIC;

public const int SPELLOUT;

public const int ORDINAL;

public const int DURATION;

public const int PATTERN_RULEBASED;

public const int IGNORE;

public const int CURRENCY_ACCOUNTING;

public const int DEFAULT_STYLE;

public const int ROUND_CEILING;

public const int ROUND_FLOOR;

public const int ROUND_DOWN;

public const int ROUND_UP;

public const int ROUND_HALFEVEN;

public const int ROUND_HALFDOWN;

public const int ROUND_HALFUP;

public const int PAD_BEFORE_PREFIX;

public const int PAD_AFTER_PREFIX;

public const int PAD_BEFORE_SUFFIX;

public const int PAD_AFTER_SUFFIX;

public const int PARSE_INT_ONLY;

public const int GROUPING_USED;

public const int DECIMAL_ALWAYS_SHOWN;

public const int MAX_INTEGER_DIGITS;

public const int MIN_INTEGER_DIGITS;

public const int INTEGER_DIGITS;

public const int MAX_FRACTION_DIGITS;

public const int MIN_FRACTION_DIGITS;

public const int FRACTION_DIGITS;

public const int MULTIPLIER;

public const int GROUPING_SIZE;

public const int ROUNDING_MODE;

public const int ROUNDING_INCREMENT;

public const int FORMAT_WIDTH;

public const int PADDING_POSITION;

public const int SECONDARY_GROUPING_SIZE;

public const int SIGNIFICANT_DIGITS_USED;

public const int MIN_SIGNIFICANT_DIGITS;

public const int MAX_SIGNIFICANT_DIGITS;

public const int LENIENT_PARSE;

public const int POSITIVE_PREFIX;

public const int POSITIVE_SUFFIX;

public const int NEGATIVE_PREFIX;

public const int NEGATIVE_SUFFIX;

public const int PADDING_CHARACTER;

public const int CURRENCY_CODE;

public const int DEFAULT_RULESET;

public const int PUBLIC_RULESETS;

public const int DECIMAL_SEPARATOR_SYMBOL;

public const int GROUPING_SEPARATOR_SYMBOL;

public const int PATTERN_SEPARATOR_SYMBOL;

public const int PERCENT_SYMBOL;

public const int ZERO_DIGIT_SYMBOL;

public const int DIGIT_SYMBOL;

public const int MINUS_SIGN_SYMBOL;

public const int PLUS_SIGN_SYMBOL;

public const int CURRENCY_SYMBOL;

public const int INTL_CURRENCY_SYMBOL;

public const int MONETARY_SEPARATOR_SYMBOL;

public const int EXPONENTIAL_SYMBOL;

public const int PERMILL_SYMBOL;

public const int PAD_ESCAPE_SYMBOL;

public const int INFINITY_SYMBOL;

public const int NAN_SYMBOL;

public const int SIGNIFICANT_DIGIT_SYMBOL;

public const int MONETARY_GROUPING_SEPARATOR_SYMBOL;

public const int TYPE_DEFAULT;

public const int TYPE_INT32;

public const int TYPE_INT64;

public const int TYPE_DOUBLE;

public const int TYPE_CURRENCY;

/* Metodi */

public __construct(string $locale, int $style, ?string $pattern = null)

public static create(string $locale, int $style, ?string $pattern = null): ?NumberFormatter

public format(int|float $num, int $type = NumberFormatter::TYPE_DEFAULT): string|false

public formatCurrency(float $amount, string $currency): string|false

public getAttribute(int $attribute): int|float|false

public getErrorCode(): int

public getErrorMessage(): string

public getLocale(int $type = ULOC_ACTUAL_LOCALE): string|false

public getPattern(): string|false

public getSymbol(int $symbol): string|false

public getTextAttribute(int $attribute): string|false

public parse(string $string, int $type = NumberFormatter::TYPE_DOUBLE, int &$offset = null): int|float|false

public parseCurrency(string $string, string &$currency, int &$offset = null): float|false

public setAttribute(int $attribute, int|float $value): bool

public setPattern(string $pattern): bool

public setSymbol(int $symbol, string $value): bool

public setTextAttribute(int $attribute, string $value): bool

}

Costanti predefinite

Format Types

These styles are used by the numfmt_create() to define the type of the formatter.

NumberFormatter::PATTERN_DECIMAL: Decimal format defined by pattern
NumberFormatter::DECIMAL: Decimal format
NumberFormatter::CURRENCY: Currency format
NumberFormatter::PERCENT: Percent format
NumberFormatter::SCIENTIFIC: Scientific format
NumberFormatter::SPELLOUT: Spellout rule-based format
NumberFormatter::ORDINAL: Ordinal rule-based format
NumberFormatter::DURATION: Duration rule-based format
NumberFormatter::PATTERN_RULEBASED: Rule-based format defined by pattern
NumberFormatter::CURRENCY_ACCOUNTING: Currency format for accounting, e.g., ($3.00) for negative currency amount instead of -$3.00. Available as of PHP 7.4.1 and ICU 53.
NumberFormatter::DEFAULT_STYLE: Default format for the locale
NumberFormatter::IGNORE: Alias for PATTERN_DECIMAL

Number Format Specifiers

These constants define how the numbers are parsed or formatted. They should be used as arguments to numfmt_format() and numfmt_parse().

NumberFormatter::TYPE_DEFAULT: Derive the type from variable type
NumberFormatter::TYPE_INT32: Format/parse as 32-bit integer
NumberFormatter::TYPE_INT64: Format/parse as 64-bit integer
NumberFormatter::TYPE_DOUBLE: Format/parse as floating point value
NumberFormatter::TYPE_CURRENCY: Format/parse as currency value. Deprecated as of PHP 8.3.0

Number Format Attributes

Number format attribute used by numfmt_get_attribute() and numfmt_set_attribute().

NumberFormatter::PARSE_INT_ONLY: Parse integers only.
NumberFormatter::GROUPING_USED: Use grouping separator.
NumberFormatter::DECIMAL_ALWAYS_SHOWN: Always show decimal point.
NumberFormatter::MAX_INTEGER_DIGITS: Maximum integer digits.
NumberFormatter::MIN_INTEGER_DIGITS: Minimum integer digits.
NumberFormatter::INTEGER_DIGITS: Integer digits.
NumberFormatter::MAX_FRACTION_DIGITS: Maximum fraction digits.
NumberFormatter::MIN_FRACTION_DIGITS: Minimum fraction digits.
NumberFormatter::FRACTION_DIGITS: Fraction digits.
NumberFormatter::MULTIPLIER: Multiplier.
NumberFormatter::GROUPING_SIZE: Grouping size.
NumberFormatter::ROUNDING_MODE: Rounding Mode.
NumberFormatter::ROUNDING_INCREMENT: Rounding increment.
NumberFormatter::FORMAT_WIDTH: The width to which the output of format() is padded.
NumberFormatter::PADDING_POSITION: The position at which padding will take place. See pad position constants for possible argument values.
NumberFormatter::SECONDARY_GROUPING_SIZE: Secondary grouping size.
NumberFormatter::SIGNIFICANT_DIGITS_USED: Use significant digits.
NumberFormatter::MIN_SIGNIFICANT_DIGITS: Minimum significant digits.
NumberFormatter::MAX_SIGNIFICANT_DIGITS: Maximum significant digits.
NumberFormatter::LENIENT_PARSE: Lenient parse mode used by rule-based formats.

Number Format Text Attributes

Number format text attribute used by numfmt_get_text_attribute() and numfmt_set_text_attribute().

NumberFormatter::POSITIVE_PREFIX: Positive prefix.
NumberFormatter::POSITIVE_SUFFIX: Positive suffix.
NumberFormatter::NEGATIVE_PREFIX: Negative prefix.
NumberFormatter::NEGATIVE_SUFFIX: Negative suffix.
NumberFormatter::PADDING_CHARACTER: The character used to pad to the format width.
NumberFormatter::CURRENCY_CODE: The ISO currency code.
NumberFormatter::DEFAULT_RULESET: The default rule set. This is only available with rule-based formatters.
NumberFormatter::PUBLIC_RULESETS: The public rule sets. This is only available with rule-based formatters. This is a read-only attribute. The public rulesets are returned as a single string, with each ruleset name delimited by ';' (semicolon).

Symbol Format Specifiers

Number format symbols used by numfmt_get_symbol() and numfmt_set_symbol().

NumberFormatter::DECIMAL_SEPARATOR_SYMBOL: The decimal separator.
NumberFormatter::GROUPING_SEPARATOR_SYMBOL: The grouping separator.
NumberFormatter::PATTERN_SEPARATOR_SYMBOL: The pattern separator.
NumberFormatter::PERCENT_SYMBOL: The percent sign.
NumberFormatter::ZERO_DIGIT_SYMBOL: Zero.
NumberFormatter::DIGIT_SYMBOL: Character representing a digit in the pattern.
NumberFormatter::MINUS_SIGN_SYMBOL: The minus sign.
NumberFormatter::PLUS_SIGN_SYMBOL: The plus sign.
NumberFormatter::CURRENCY_SYMBOL: The currency symbol.
NumberFormatter::INTL_CURRENCY_SYMBOL: The international currency symbol.
NumberFormatter::MONETARY_SEPARATOR_SYMBOL: The monetary separator.
NumberFormatter::EXPONENTIAL_SYMBOL: The exponential symbol.
NumberFormatter::PERMILL_SYMBOL: Per mill symbol.
NumberFormatter::PAD_ESCAPE_SYMBOL: Escape padding character.
NumberFormatter::INFINITY_SYMBOL: Infinity symbol.
NumberFormatter::NAN_SYMBOL: Not-a-number symbol.
NumberFormatter::SIGNIFICANT_DIGIT_SYMBOL: Significant digit symbol.
NumberFormatter::MONETARY_GROUPING_SEPARATOR_SYMBOL: The monetary grouping separator.

Rounding Modes

Rounding mode values used by numfmt_get_attribute() and numfmt_set_attribute() with NumberFormatter::ROUNDING_MODE attribute.

NumberFormatter::ROUND_CEILING: Rounding mode to round towards positive infinity.
NumberFormatter::ROUND_DOWN: Rounding mode to round towards zero.
NumberFormatter::ROUND_FLOOR: Rounding mode to round towards negative infinity.
NumberFormatter::ROUND_HALFDOWN: Rounding mode to round towards "nearest neighbor" unless both neighbors are equidistant, in which case round down.
NumberFormatter::ROUND_HALFEVEN: Rounding mode to round towards the "nearest neighbor" unless both neighbors are equidistant, in which case, round towards the even neighbor.
NumberFormatter::ROUND_HALFUP: Rounding mode to round towards "nearest neighbor" unless both neighbors are equidistant, in which case round up.
NumberFormatter::ROUND_UP: Rounding mode to round away from zero.

Padding Specifiers

Pad position values used by numfmt_get_attribute() and numfmt_set_attribute() with NumberFormatter::PADDING_POSITION attribute.

NumberFormatter::PAD_AFTER_PREFIX: Pad characters inserted after the prefix.
NumberFormatter::PAD_AFTER_SUFFIX: Pad characters inserted after the suffix.
NumberFormatter::PAD_BEFORE_PREFIX: Pad characters inserted before the prefix.
NumberFormatter::PAD_BEFORE_SUFFIX: Pad characters inserted before the suffix.

Vedere anche:

Indice dei contenuti

NumberFormatter::create — Create a number formatter
NumberFormatter::format — Format a number
NumberFormatter::formatCurrency — Format a currency value
NumberFormatter::getAttribute — Get an attribute
NumberFormatter::getErrorCode — Get formatter's last error code
NumberFormatter::getErrorMessage — Get formatter's last error message
NumberFormatter::getLocale — Get formatter locale
NumberFormatter::getPattern — Get formatter pattern
NumberFormatter::getSymbol — Get a symbol value
NumberFormatter::getTextAttribute — Get a text attribute
NumberFormatter::parse — Parse a number
NumberFormatter::parseCurrency — Parse a currency number
NumberFormatter::setAttribute — Set an attribute
NumberFormatter::setPattern — Set formatter pattern
NumberFormatter::setSymbol — Set a symbol value
NumberFormatter::setTextAttribute — Set a text attribute

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User Contributed Notes 8 notes

down

giorgio dot liscio at email dot it ¶

13 years ago

this class seems to be painful: it is not, formatting and parsing are highly customizable, but what you probably need is really simple:



if you want to localize a number use:



<?php

$a = new \NumberFormatter("it-IT", \NumberFormatter::DECIMAL);

echo $a->format(12345.12345) . "<br>"; // outputs 12.345,12

$a->setAttribute(\NumberFormatter::MIN_FRACTION_DIGITS, 0);

$a->setAttribute(\NumberFormatter::MAX_FRACTION_DIGITS, 100); // by default some locales got max 2 fraction digits, that is probably not what you want

echo $a->format(12345.12345) . "<br>"; // outputs 12.345,12345

?>



if you want to print money use:



<?php

$a = new \NumberFormatter("it-IT", \NumberFormatter::CURRENCY);

echo $a->format(12345.12345) . "<br>"; // outputs €12.345,12

?>



if you have money data stored as (for example) US dollars and you want to print them using the it-IT notation, you need to use



<?php

$a = new \NumberFormatter("it-IT", \NumberFormatter::CURRENCY);

echo $a->formatCurrency(12345, "USD") . "<br>"; // outputs $ 12.345,00 and it is formatted using the italian notation (comma as decimal separator)

?>



another useful example about currency (how to obtain the currency name by a locale string):



<?php

$frontEndFormatter = new \NumberFormatter("it-IT", \NumberFormatter::CURRENCY);

$adminFormatter = new \NumberFormatter("en-US", \NumberFormatter::CURRENCY);

$symbol = $adminFormatter->getSymbol(\NumberFormatter::INTL_CURRENCY_SYMBOL); // got USD

echo $frontEndFormatter->formatCurrency(12345.12345,  $symbol) . "<br>";

?>

down

jimbo2150 at gmail dot com ¶

1 year ago

The NumberFormatter class can be used to convert integer numbers to Roman numerals without a custom function using an array of symbols and associated values:

<?php

function intToRomanNumeral(int $num) {
    static $nf = new NumberFormatter('@numbers=roman', NumberFormatter::DECIMAL);
    return $nf->format($num);
}

echo intToRomanNumeral(2); // II

echo intToRomanNumeral(5); // V

echo intToRomanNumeral(10); // X

echo intToRomanNumeral(50); // L

echo intToRomanNumeral(57); // LVII
echo intToRomanNumeral(58); // LVIII

echo intToRomanNumeral(100); // C

echo intToRomanNumeral(150); // CL

echo intToRomanNumeral(1000); // M

echo intToRomanNumeral(10000); // ↂ

?>

down

stan at dragnev dot ca ¶

4 years ago

Here's an example of how to use PATTERN_DECIMAL to print a number with two fraction digits, use () for negative numbers and pad to five characters to the left of the decimal point, using spaces as the padding character:

<?php

$fmt = new NumberFormatter("en-CA", NumberFormatter::PATTERN_DECIMAL, "* #####.00 ;(* #####.00)");
echo $fmt->format(-45.1);

// Outputs: "  (45.10)"

?>

Note that the ; in the pattern denotes the beginning of a subpattern, which is used for negative numbers. Hence the brackets around the pattern after the semicolon.

down

Einenlum ¶

9 months ago

Be aware that (at least with the locale 'fr-FR') NumberFormatter doesn't use spaces. It doesn't even use non breakable spaces (NBSP). It uses narrow non breakable spaces (NNBSP). This broke my tests.

<?php

$formatter = new NumberFormatter(
    'fr-FR',
    NumberFormatter::DEFAULT_STYLE
);

$value = $formatter->format(100_000); // '100 000'

// If you want to replace narrow non breakable spaces with non breakable spaces:

str_replace("\u{202F}", "\u{00A0}", $value);

// If you want to replace it with a normal space

str_replace("\u{202F}", " ", $value);

down

sudheer at binaryvibes dot co dot in ¶

13 years ago

Sample script to print number in English.

<?php
$f = new NumberFormatter("en", NumberFormatter::SPELLOUT);
echo $f->format(123456);

?>

Produces the result:
one hundred twenty-three thousand four hundred fifty-six

down

gwyneth dot llewelyn at gwynethllewelyn dot net ¶

2 years ago

When using the `NumberFormatter` class for pretty-printing currency in PHP 7.3 and 8+, it's not clear from the documentation that you can use the empty string "" as the locale for the constructor, and that will retrieve the default locale (whatever it has been set to in your environment).

`formatCurrency()`, by contrast, does not accept the empty string for the default currency symbol; it will display a 'generic' currency symbol instead (¤).

Tested with PHP 7.4.30, 8.0.21, 8.1.8 under Ubuntu Linux and 8.1.8 under macOS Big Sur (11.6.8). I tried under other alternatives (e.g. Linux running on ARM chips, PHP 7.3.3) but sadly the `NumberFormatter` library does not seem to be present (or could not be found) on those systems...

down

-2

AF ¶

3 years ago

Please pay attention to the Arabic decimal separator (https://en.wikipedia.org/wiki/Decimal_separator#Other_numeral_systems).

All the following conditions are true:
<?php
(new \NumberFormatter("ar_AE", \NumberFormatter::DEFAULT_STYLE))->getSymbol(\NumberFormatter::DECIMAL_SEPARATOR_SYMBOL) === '٫';
(new \NumberFormatter("ar_AE", \NumberFormatter::DEFAULT_STYLE))->getSymbol(\NumberFormatter::DECIMAL_SEPARATOR_SYMBOL) == '٫';

(new \NumberFormatter("ar_AE", \NumberFormatter::DEFAULT_STYLE))->getSymbol(\NumberFormatter::DECIMAL_SEPARATOR_SYMBOL) !== ',';
(new \NumberFormatter("ar_AE", \NumberFormatter::DEFAULT_STYLE))->getSymbol(\NumberFormatter::DECIMAL_SEPARATOR_SYMBOL) != ',';
?>

down

-3

Joey ¶

7 years ago

Be warned that this class sometimes lacks sufficient error output. I recently instantiated it while invalid pattern to the constructor.

    php -r '$nf = new \NumberFormatter("tlh-KX.UTF8", \NumberFormatter::IGNORE, "{,,#;#}");var_dump($nf->format(5));'

    Fatal error: Call to a member function format() on null in Command line code on line 1

Rather than emitting an error message or throwing an exception null is returned after calling new.

I'm not sure if it's fixed in PHP 7 but it's something to watch out for. Make sure you check your parameters very closely.

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