PHP function: generate N non-repeating random numbers, php random numbers_PHP tutorial

PHP function: generate N non-repeating random numbers, php random number

PHP function: generate N non-repeating random numbers

Idea: Store the generated random numbers in an array, and then remove duplicate values ​​from the array to generate a certain number of non-repeating random numbers.

Program:

<?php
/*
* array unique_rand( int $min, int $max, int $num )
* 生成一定数量的不重复随机数
* $min 和 $max: 指定随机数的范围
* $num: 指定生成数量
*/

function  unique_rand($min,$max,$num){
    $count = 0;
    $return_arr = array();
    while($count < $num){
        $return_arr[] = mt_rand($min,$max);
        $return_arr = array_flip(array_flip($return_arr));
        $count = count($return_arr);
    }
    shuffle($return_arr);
    return $return_arr;
}

Additional instructions:

1. The mt_rand() function is used to generate random numbers. This function is 4 times faster than the rand() function;

2. When removing duplicate values ​​from an array, the "flip method" is used, which is to use array_flip() to exchange the key and value of the array twice. Much faster than using array_unique().