PHP中round()函數(shù)對浮點(diǎn)數(shù)進(jìn)行四舍五入的方法

2024-05-04 23:27:38

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這篇文章主要介紹了PHP中round()函數(shù)對浮點(diǎn)數(shù)進(jìn)行四舍五入的方法,通過詳盡的實(shí)例對round()函數(shù)的各種常見用法進(jìn)行了歸納整理,是非常實(shí)用的技巧,需要的朋友可以參考下

本文實(shí)例講述了PHP中round()函數(shù)對浮點(diǎn)數(shù)進(jìn)行四舍五入的方法。分享給大家供大家參考。具體方法如下：

語法:round(x,prec)

參數(shù)	描述
x	可選,規(guī)定要舍入的數(shù)字.
prec	可選,規(guī)定小數(shù)點(diǎn)后的位數(shù).

說明:返回將 x 根據(jù)指定精度 prec(十進(jìn)制小數(shù)點(diǎn)后數(shù)字的數(shù)目)進(jìn)行四舍五入的結(jié)果,prec 也可以是負(fù)數(shù)或零(默認(rèn)值).

提示和注釋

注釋:php默認(rèn)不能正確處理類似 "12,300.2" 的字符串.

注釋:prec 參數(shù)是在 php 4 中被引入的,實(shí)例代碼如下:

復(fù)制代碼代碼如下:

		<?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(shù)代替php的round函數(shù) 
		?>

復(fù)制代碼代碼如下:

		<?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 "; 
		?>