$num = 10.4567;         //第一种：利用round()对浮点数进行四舍五入    echo round($num,2); //10.46         //第二种：利用sprintf格式化字符串    $format_num = sprintf("%.2f",$num);    echo $format_num; //10.46         //第三种：利用千位分组来格式化数字的函数number_format()    echo number_format($num, 2); //10.46    //或者如下    echo number_format($num, 2, '.', ''); //10/46