PHP - Pick randomly from array - allowing duplicates

Create $amount again with random number if it is more than $this->specials

$amount = $amount<=count($this->specials)?$amount: rand(0,count($this->specials));
$cardsList = array_rand($this->specials, $amount);

You could just write a function that will do what you desire:

function getRandomArrayValues($arr, $amount){
   $result = array();
   for($i = 0; $i < amount; $i++){
      $result[$i] = array_rand($arr, 1);
   }
  return $result;
}

Your approach is fairly common, since array_rand only returns an array of randomized keys of the supplied array, or returns a single random key from the array when supplying 1 as the amount, you will be forced to use a for loop to retrieve the desired amount, and leads to reduced performance when a very large amount is requested.

An alternative to array_rand is using shuffle. To resolve a desired amount larger than the source array, use array_merge to fill the array until the desired amount is reached. Then use array_slice to reduce the shuffled array to exactly the desired amount.

Example: https://3v4l.org/LDSj4

//create an array of 8 values - for this example
$a = range('A', 'H');

//specify a larger amount of values to retrieve
$amount = 20;
//this only occurs when the array is smaller than the amount
while (count($a) < $amount) {
    //fill the array exponentially with the same values until amount is reached
    $a = array_merge($a, $a);
}
//randomize the array order
shuffle($a);
//reduce the array to the desired amount
$a = array_slice($a, 0, $amount);
var_dump($a);

Example Results (results vary as seen in the example link);

array(20) {
  [0]=>
  string(1) "F"
  [1]=>
  string(1) "B"
  [2]=>
  string(1) "E"
  [3]=>
  string(1) "B"
  [4]=>
  string(1) "H"
  [5]=>
  string(1) "A"
  [6]=>
  string(1) "C"
  [7]=>
  string(1) "C"
  [8]=>
  string(1) "C"
  [9]=>
  string(1) "G"
  [10]=>
  string(1) "G"
  [11]=>
  string(1) "H"
  [12]=>
  string(1) "D"
  [13]=>
  string(1) "F"
  [14]=>
  string(1) "A"
  [15]=>
  string(1) "G"
  [16]=>
  string(1) "E"
  [17]=>
  string(1) "C"
  [18]=>
  string(1) "E"
  [19]=>
  string(1) "D"
}

@Ceri Turner unfortunately array_rand() will not accept $amount if it is larger than your source array count. You have to write custom function, you don't have any other in built function.

After looking into some suggestions from @fyrye I'd done some modification into the function as given. It can also randomize more efficiently than previous one.

You can check live example https://3v4l.org/tPc7A

<?php

function randomizer($sArray, $target) 
{
    $b = (count($sArray)/2); // Randomize count for better result make it half of the total array count
    $c = floor($target/$b); // Loop Count
    $r = $target-($b*$c); // Rest of the Count
    $cardsList = array();
    if($c > 0){
        /* Now Loop for Full Number */
        for($i=0; $i<$c; $i++){
            $cardsList = array_merge($cardsList,array_rand($sArray, $b));
        }
        if($r >= 1){
            $restArray = array_rand($sArray, $r);
            if(is_array($restArray)){
                $cardsList = array_merge($cardsList,$restArray);
            }else{
                $cardsList[] = $restArray;
            }
        }
    }else{
        $cardsList = array_merge($cardsList,array_rand($sArray, $target));
    }
    return $cardsList;
}

//only 8 values
$sArray = range('A', 'H');

$resultArray = randomizer($sArray, 67);
echo 'Amount 50 -  result: ' . count($resultArray) . \PHP_EOL; 
print_r($resultArray);
?>