<?php
$num = '10.4567';
//第一种:利用round()对浮点数进行四舍五入
echo round($num,2).PHP_EOL; //10.46
//第二种:利用sprintf格式化字符串
$format_num = sprintf('%.2f',$num);
echo $format_num.PHP_EOL; //10.46
//第三种:利用千位分组来格式化数字的函数number_format()
echo number_format($num, 2).PHP_EOL; //10.46
//或者如下
echo number_format($num, 2, '.', ''); //10.46