《PHP實例：PHP中round()函數對浮點數進行四舍五入的方法》要點：
本文介紹了PHP實例：PHP中round()函數對浮點數進行四舍五入的方法，希望對您有用。如果有疑問，可以聯系我們。
PHP學習本文實例講述了PHP中round()函數對浮點數進行四舍五入的辦法.分享給大家供大家參考.具體辦法如下：
PHP學習語法:round(x,prec)
| 參數 |
描述 |
| x |
可選,規定要舍入的數字. |
| prec |
可選,規定小數點后的位數. |
PHP學習說明:返回將 x 根據指定精度 prec(十進制小數點后數字的數目)進行四舍五入的結果,prec 也可以是負數或零(默認值).
PHP學習提示和注釋
PHP學習注釋:php默認不能正確處理類似 "12,300.2" 的字符串.
PHP學習注釋:prec 參數是在 php 4 中被引入的,實例代碼如下:
代碼如下:
<?php
*/
echo round(3.4);???????? //輸出3
echo "<br>";
echo round(3.5);???????? //輸出4
echo "<br>";
echo round(3.6);???????? //輸出4
echo "<br>";
echo round(3.6,0);???????? //輸出4
echo "<br>";
echo round(1.95583,2);??????? //輸出1.96
echo "<br>";
echo round(1241757,-3);??????? //輸出1242000
echo "<br>";
echo round(4.045,2);???????? //輸出4.05
echo "<br>";
echo round(4.055,2);???????? //輸出4.06
?
//使用stdround函數代替php的round函數
?>
?
代碼如下:
<?php
function?? stdround($num,?? $d=0)?
{?
????? return?? round($num?? +?? 0.0001?? /?? pow(10,?? $d),?? $d);?
}???
????????
echo?? "round(1.005,2)= ".round(1.005,2). "n ";?
echo?? "round(1.015,2)= ".round(1.015,2). "n ";?
echo?? "round(1.025,2)= ".round(1.025,2). "n ";?
echo?? "round(1.035,2)= ".round(1.035,2). "n ";?
echo?? "round(1.045,2)= ".round(1.045,2). "n ";?
echo?? "round(1.055,2)= ".round(1.055,2). "n ";?
echo?? "round(1.065,2)= ".round(1.065,2). "n ";?
echo?? "round(1.075,2)= ".round(1.075,2). "n ";?
echo?? "round(1.085,2)= ".round(1.085,2). "n ";?
echo?? "round(1.095,2)= ".round(1.095,2). "n ";
?
echo?? "stdround(1.005,2)= ".stdround(1.005,2). "n ";?
echo?? "stdround(1.015,2)= ".stdround(1.015,2). "n ";?
echo?? "stdround(1.025,2)= ".stdround(1.025,2). "n ";?
echo?? "stdround(1.035,2)= ".stdround(1.035,2). "n ";?
echo?? "stdround(1.045,2)= ".stdround(1.045,2). "n ";?
echo?? "stdround(1.055,2)= ".stdround(1.055,2). "n ";?
echo?? "stdround(1.065,2)= ".stdround(1.065,2). "n ";?
echo?? "stdround(1.075,2)= ".stdround(1.075,2). "n ";?
echo?? "stdround(1.085,2)= ".stdround(1.085,2). "n ";?
echo?? "stdround(1.095,2)= ".stdround(1.095,2). "n ";
?
$m=0.000000000000001;?
echo?? "n ";?
echo?? "round(1.005+{$m},2)= ".round(1.005+$m,2). "n ";?
echo?? "round(1.015+{$m},2)= ".round(1.015+$m,2). "n ";?
echo?? "round(1.025+{$m},2)= ".round(1.025+$m,2). "n ";?
echo?? "round(1.035+{$m},2)= ".round(1.035+$m,2). "n ";?
echo?? "round(1.045+{$m},2)= ".round(1.045+$m,2). "n ";?
echo?? "round(1.055+{$m},2)= ".round(1.055+$m,2). "n ";?
echo?? "round(1.065+{$m},2)= ".round(1.065+$m,2). "n ";?
echo?? "round(1.075+{$m},2)= ".round(1.075+$m,2). "n ";?
echo?? "round(1.085+{$m},2)= ".round(1.085+$m,2). "n ";?
echo?? "round(1.095+{$m},2)= ".round(1.095+$m,2). "n ";
?
echo?? "round(1.005,2)= ".round(1.005,2). "n ";?
echo?? "round(1.015,2)= ".round(1.015,2). "n ";?
echo?? "round(1.025,2)= ".round(1.025,2). "n ";?
echo?? "round(1.035,2)= ".round(1.035,2). "n ";?
echo?? "round(1.045,2)= ".round(1.045,2). "n ";?
echo?? "round(1.055,2)= ".round(1.055,2). "n ";?
echo?? "round(1.065,2)= ".round(1.065,2). "n ";?
echo?? "round(1.075,2)= ".round(1.075,2). "n ";?
echo?? "round(1.085,2)= ".round(1.085,2). "n ";?
echo?? "round(1.095,2)= ".round(1.095,2). "n ";
?>
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