$num = 10.4567;
     
    //第一種：利用round()對(duì)浮點(diǎn)數(shù)進(jìn)行四舍五入
    echo round($num,2); //10.46
     
    //第二種：利用sprintf格式化字符串
    $format_num = sprintf("%.2f",$num);
    echo $format_num; //10.46
     
    //第三種：利用千位分組來(lái)格式化數(shù)字的函數(shù)number_format()
    echo number_format($num, 2); //10.46
    //或者如下
    echo number_format($num, 2, '.', ''); //10/46