If you're looking for the pattern syntax, their documentation is here: http://unicode.org/reports/tr35/tr35-numbers.html#Number_Format_Patterns
(PHP 5 >= 5.3.0, PHP 7, PHP 8, PECL intl >= 1.0.0)
NumberFormatter::setPattern -- numfmt_set_pattern — Set formatter pattern
Object-oriented style
Procedural style
Set the pattern used by the formatter. Can not be used on a rule-based formatter.
formatter
NumberFormatter object.
pattern
Pattern in syntax described in » ICU DecimalFormat documentation.
Example #1 numfmt_set_pattern() example
<?php
$fmt = numfmt_create( 'de_DE', NumberFormatter::DECIMAL );
echo "Pattern: ".numfmt_get_pattern($fmt)."\n";
echo numfmt_format($fmt, 1234567.891234567890000)."\n";
numfmt_set_pattern($fmt, "#0.# kg");
echo "Pattern: ".numfmt_get_pattern($fmt)."\n";
echo numfmt_format($fmt, 1234567.891234567890000)."\n";
?>
Example #2 OO example
<?php
$fmt = new NumberFormatter( 'de_DE', NumberFormatter::DECIMAL );
echo "Pattern: ".$fmt->getPattern()."\n";
echo $fmt->format(1234567.891234567890000)."\n";
$fmt->setPattern("#0.# kg");
echo "Pattern: ".$fmt->getPattern()."\n";
echo $fmt->format(1234567.891234567890000)."\n";
?>
The above example will output:
Pattern: #,##0.### 1.234.567,891 Pattern: #0.# kg 1234567,9 kg
If you're looking for the pattern syntax, their documentation is here: http://unicode.org/reports/tr35/tr35-numbers.html#Number_Format_Patterns
setPattern appears to influence only the behavior of the format method, not the parse method of the NumberFormatter object.
$pattern = '#,##0';
$frmtr = NumberFormatter::create('en-US', NumberFormatter::DECIMAL);
$frmtr->setPattern($pattern);
echo $frmtr->parse('12.345');
// returns 12