#php generate unique random numbers within a range

unique-random.php

<?php

//https://stackoverflow.com/a/24493651
function unique_randoms($min, $max, $count) {
 $arr = array();
 while(count($arr) < $count){
      $tmp =mt_rand($min,$max);
      if(!in_array($tmp, $arr)){
         $arr[] = $tmp;
      }
 }
return $arr;
}

//https://stackoverflow.com/a/28154388
//avoids the use of in_array and doesn't generate a huge array. 
//So, it is fast and preserves a lot of memory.
function getDistinctRandomNumbers ($nb, $min, $max) {
    if ($max - $min + 1 < $nb)
        return false; // or throw an exception

    $res = array();
    do {
        $res[mt_rand($min, $max)] = 1;
    } while (count($res) !== $nb);
    return array_keys($res); 
}


// return unique_randoms(20, 100, 20);
return getDistinctRandomNumbers(20, 20, 100);