round() 函数对浮点数进行四舍五入
语法: round(x,prec)
参数 描述
x 可选,规定要舍入的数字.
prec 可选,规定小数点后的位数.
说明: 返回将 x 根据指定精度 prec(十进制小数点后数字的数目)进行四舍五入的结果,prec 也可以是负数或零(默认值).
提示和注释
注释: php默认不能正确处理类似 "12,300.2" 的字符串.
注释:prec 参数是在 php 4 中被引入的,实例代码如下:
<?php */ echo round (3.4); //输出3 echo "<br>" ; echo round (3.5); //输出4 echo "<br>" ; echo round (3.6); //输出4 echo "<br>" ; echo round (3.6,0); //输出4 echo "<br>" ; echo round (1.95583,2); //输出1.96 echo "<br>" ; echo round (1241757,-3); //输出1242000 echo "<br>" ; echo round (4.045,2); //输出4.05 //开源代码phpfensi测试数据 echo "<br>" ; echo round (4.055,2); //输出4.06 //使用stdround函数代替php的round函数 ?> <?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 " ; ?>查看更多关于round() 函数对浮点数进行四舍五入 - php函数的详细内容...
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