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Homephp教程php手册PHP生成不重复随机数的方法汇总

本文汇总了5种生成不重复随机数的方法,其中方法一、二、三是本人常用的方法,方法四五来至度娘。其余方法还是有的,也欢迎大家将遗漏的方法告之,大家共同进步

无论是Web应用,还是WAP或者移动应用,随机数都有其用武之地。在最近接触的几个小项目中,我也经常需要和随机数或者随机数组打交道,所以,对于PHP如何产生不重复随机数常用的几种方法小结一下。

方法一:

复制代码 代码如下:


$numbers = range (1,50);
//shuffle 将数组顺序随即打乱
shuffle ($numbers);
//array_slice 取该数组中的某一段
$num=6;
$result = array_slice($numbers,0,$num);
print_r($result);
?>

方法二:

复制代码 代码如下:


$numbers = range (1,20);
//播下随机数发生器种子,可有可无,测试后对结果没有影响
srand ((float)microtime()*1000000);
shuffle ($numbers);
//跳过list第一个值(保存的是索引)
while (list(, $number) = each ($numbers)) {
echo "$number ";
}
?>

方法三:

复制代码 代码如下:


function NoRand($begin=0,$end=20,$limit=5){
$rand_array=range($begin,$end);
shuffle($rand_array);//调用现成的数组随机排列函数
return array_slice($rand_array,0,$limit);//截取前$limit个
}
print_r(NoRand());
?>

上述可以在1-20间随机产生5个不重复的值

方法四:

复制代码 代码如下:


$tmp=array();
while(count($tmp) $tmp[]=mt_rand(1,20);
$tmp=array_unique($tmp);
}
print_r($tmp);
?>

方法五:

复制代码 代码如下:


$tmp = range(1,30);
print_r(array_rand($tmp,10));
?>

这个可能是比叫简单的了(ps:如果在range中指定了步长,就必须注意array_rand的第二个参数是否超出$tmp的长度)。

PHP提供非常丰富的数组函数,产生随机数大多可以从数组这个角度出发,当然如果你有更好的方法,也请告之,本文也算是抛砖引玉了。

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