这里列举了三中方法:
$number = 12.34567;
echo '1.round()进行四舍五入:'. round($number,3); //10.46
echo "<br>";
echo "2.sprintf格式化:". sprintf("%.2f",$number);
echo "<br>";
echo "3.使用number_format()格式化:". number_format($number, 3); //10.46