Detailed explanation of generating N non-repeating random number instances in PHP_PHP Tutorial

I have told you about generating multiple random numbers before. Now I will introduce an example of generating N non-repeating random numbers in PHP. If you are interested, you can refer to it.

It is not difficult to implement this function, but it made me learn a lot.

* Generate a certain number of unique random numbers

The code is as follows

代码如下

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/**   * 生成一定数量的不重复随机数   * @param int $min ,$max指定随机数的范围   * @param int $max   * @param int $num 指定生成数量   * @return array   */ function unique_rand($min, $max, $num) {      $count = 0;      $return = array();      while ($count < $num) {          $return[] = mt_rand($min, $max);          $return = array_flip(array_flip($return));          $count = count($return);      }      shuffle($return);      return $return;  }

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/**

* @param int $min, $max specifies the range of random numbers

* @param int $max

* @param int $num specifies the number of generated * @return array */ function unique_rand($min, $max, $num) { $count = 0; $return = array();

while ($count < $num) { $return[] = mt_rand($min, $max);

$return = array_flip(array_flip($return)); $count = count($return); } shuffle($return); return $return; } The mt_rand() function is used to generate random numbers. This function generates random numbers four times faster on average than rand(). The "flip method" is used to remove duplicate values ​​in the array, which is to use array_flip() to exchange the key and value of the array twice. This approach is much faster than using array_unique(). Before returning the array, first use shuffle() to assign new key names to the array, ensuring that the key names are consecutive numbers from 0-n. If this step is not performed, key names may become discontinuous when deleting duplicate values, causing trouble in traversal. http://www.bkjia.com/PHPjc/633145.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/633145.htmlTechArticleI have told you about generating multiple random numbers before. Now I will introduce another article about generating N random numbers in PHP. Examples of non-repeating random numbers. If you are interested, you can refer to it. To achieve this...