(PHP 4, PHP 5, PHP 7, PHP 8)
number_format — 以千位分隔符方式格式化一个数字
$num,$decimals = 0,$decimal_separator = ".",$thousands_separator = ","使用四舍五入的规则，将数字格式化为千位分组和小数位（可选）。
num要格式化的数字。
decimals
设置小数位数。如果为 0，则从返回值中忽略 decimal_separator。自
PHP 8.3.0 起，当值为负数时，num 将四舍五入为小数点前的有效数字
decimals。在 PHP 8.3.0 之前，负值将被忽略并与 0 一样处理。
decimal_separator指定小数点的分隔符。
thousands_separator设置千位分隔符。
num 的格式化版本。
| 版本 | 说明 |
|---|---|
| 8.3.0 |
新增对 decimals 负值的处理。
|
| 8.0.0 | 在此版本之前，number_format() 接受一个、两个或四个参数（不会是三个）。 |
| 7.2.0 |
number_format() 现在再也不会返回 -0，之前
num 为 -0.01 的情况下可以返回 -0。
|
示例 #1 number_format() 示例
例如，法语计数通常使用两位小数，逗号（“,”）作为小数分隔符，空格（“ ”）作为千位分隔符。以下示例展示了格式化数字的各种方法：
<?php
$number = 1234.56;
// 英文计数（默认）
$english_format_number = number_format($number);
// 1,235
// 法语计数
$nombre_format_francais = number_format($number, 2, ',', ' ');
// 1 234,56
$number = 1234.5678;
// 没有千位分隔符的英文计数
$english_format_number = number_format($number, 2, '.', '');
// 1234.57
?>示例 #2 decimals 为负值
自 PHP 8.3.0 起，使用 decimals 的负值来对小数点前的有效数字的位数进行四舍五入。
<?php
$number = "1234.5678";
var_dump(number_format($number, -1));
var_dump(number_format($number, -2));
var_dump(number_format($number, -3));
?>以上示例会输出：
string(5) "1,230" string(5) "1,200" string(5) "1,000"
It's not explicitly documented; number_format also rounds:<?php$numbers = array(0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009);foreach ($numbers as $number) print $number."->".number_format($number, 2, '.', ',')."<br>";?>0.001->0.000.002->0.000.003->0.000.004->0.000.005->0.010.006->0.010.007->0.010.008->0.010.009->0.01Note: use NumberFormatter to convert in human-readable format instead user function from comments:<?phpecho NumberFormatter::create('en', NumberFormatter::SPELLOUT)->format(12309); // twelve thousand three hundred nineecho NumberFormatter::create('ru', NumberFormatter::SPELLOUT)->format(12307.5); // двенадцать тысяч триста семь целых пять десятых?>Outputs a human readable number.<?php # Output easy-to-read numbers # by james at bandit.co.nz function bd_nice_number($n) { // first strip any formatting; $n = (0+str_replace(",","",$n)); // is this a number? if(!is_numeric($n)) return false; // now filter it; if($n>1000000000000) return round(($n/1000000000000),1).' trillion'; else if($n>1000000000) return round(($n/1000000000),1).' billion'; else if($n>1000000) return round(($n/1000000),1).' million'; else if($n>1000) return round(($n/1000),1).' thousand'; return number_format($n); }?>Outputs:247,704,360 -> 247.7 million866,965,260,000 -> 867 billionIf you want to display a number ending with ,- (like 200,-) when there are no decimal characters and display the decimals when there are decimal characters i use:function DisplayDouble($value) { list($whole, $decimals) = split ('[.,]', $value, 2); if (intval($decimals) > 0) return number_format($value,2,".",","); else return number_format($value,0,".",",") .",-"; }formatting numbers may be more easy if u use number_format function.I also wrote this :function something($number){ $locale = localeconv(); return number_format($number, $locale['frac_digits'], $locale['decimal_point'], $locale['thousands_sep']);}hope this helps =)[]'sFor Zero fill - just use the sprintf() function$pr_id = 1;$pr_id = sprintf("%03d", $pr_id);echo $pr_id;//outputs 001-----------------$pr_id = 10;$pr_id = sprintf("%03d", $pr_id);echo $pr_id;//outputs 010-----------------You can change %03d to %04d, etc.I ran across an issue where I wanted to keep the entered precision of a real value, without arbitrarily rounding off what the user had submitted.I figured it out with a quick explode on the number before formatting. I could then format either side of the decimal.<?php function number_format_unlimited_precision($number,$decimal = '.') { $broken_number = explode($decimal,$number); return number_format($broken_number[0]).$decimal.$broken_number[1]; }?>