php中实现四舍五入的方法有哪些

本教程操作环境：windows7系统、PHP7.1版、DELL G3电脑

在PHP开发中，有时候我们会遇到将数据进行四舍五入的运算情况，下面分享用PHP实现数据四舍五入的3种方法，分别通过number_format()函数、round()函数和sprintf()格式化输出的方法实现四舍五入。

1、number_format() 方法实现四舍五入

number_format() 函数通过千位分组来格式化数字。

<?php
 
//定义一个float型的变量
$number = 1234.5678;
 
//English Notation (defult)
$number_format_english = number_format($number);
//1,235
$number_format_english = number_format($number, 2, '.', '');
//1234.57
 
//French Notation
$number_format_francais = number_format($number, 2, ',', '');
//1234,57
$number_format_francais = number_format($number, 3, ',', '');
//1234,568
 
echo $number_format_english;
//1234.57
echo $number_format_francais;
//1234,568

2、round()方法实现四舍五入

round() 函数对浮点数进行四舍五入。

<?php
 
//定义一个float型的变量
$number = 1234.5678;
 
//不保留小数
echo round($number);
//1235
 
//保留两位小数
echo round($number,2);
//1234.57
 
echo "<br>";
 
$number = 12345678;
 
//在千分位进行四舍五入
echo round($number,-4);
//12350000

3、sprintf() 格式化输出实现四舍五入

字符串格式化命令，主要功能是把格式化的数据写入某个字符串中。sprintf 是个变参函数。

<?php
 
//定义一个正整数
$n =  43951789;
 
//定义一个负整数
$u = -43951789;
 
// ASCII 65 is 'A'
$c = 65; 
 
printf("%%b = '%b'\n", $n); 
//%b = '10100111101010011010101101'
printf("%%c = '%c'\n", $c); 
//%c = 'A' 
printf("%%d = '%d'\n", $n); 
//%d = '43951789' 
printf("%%e = '%e'\n", $n); 
//%e = '4.395179e+7' 
printf("%%u = '%u'\n", $n); 
//%u = '43951789' 
printf("%%u = '%u'\n", $u); 
//%u = '4251015507' 
printf("%%f = '%f'\n", $n); 
//%f = '43951789.000000' 
printf("%%o = '%o'\n", $n); 
//%o = '247523255' 
printf("%%s = '%s'\n", $n); 
//%s = '43951789' 
printf("%%x = '%x'\n", $n); 
//%x = '29ea6ad' 
printf("%%X = '%X'\n", $n); 
//%X = '29EA6AD' 
printf("%%+d = '%+d'\n", $n); 
//%+d = '+43951789' 
printf("%%+d = '%+d'\n", $u); 
//%+d = '-43951789'