PHP check if an array contains a specific value every tot elements

Question

I have a long array like the following. What I need to achieve is to check if every 6 elements in this array is found the value 1. If it is not found must be added to one of the 6 elements randomly ( by replacing any of the original values ). Also if the value is found more than 2 times every 6 elements, one of them needs to be replaced with another random number.

I have already created the code that is able to generate the following array randomly. But I do not know how to check if every 6 elements the array contains the value 1, if not how to add it randomly, if found more than 1 time how to replace one of the values with another random number.

I know it s pretty hard to understand. I hope someone will be able to help.

In few words the final result should be:

Every 6 elements this array has to contain at least the value 1 for one time and no more than one time, located every 6 elements in a random position.

This is what I have done so far, this code generates the array below:

/*
We select the elements to add randomly in the final array from a DB table
*/
    $elements = parent::$db->select('_matrix_elements', 'element_id', NULL, 'ORDER BY RAND()');
    $count = count($elements) - 1; //count the total number of the elements -1 to start from zero

    $columns = 6;
    $lines = 8;

    //generating the final array
    for ($a = 1; $a <= $lines; $a++) {
        for ($b = 1; $b <= $columns; $b++) {
            $rand = rand(1,$count);
            $line['position_'.$a.'_' . $b] = $elements[$rand]['element_id'];
        }
    }

Array
(
    [position_1_1] => 14
    [position_1_2] => 6
    [position_1_3] => 5
    [position_1_4] => 6
    [position_1_5] => 9
    [position_1_6] => 8
    [position_2_1] => 11
    [position_2_2] => 7
    [position_2_3] => 6
    [position_2_4] => 1
    [position_2_5] => 7
    [position_2_6] => 5
    [position_3_1] => 14
    [position_3_2] => 5
    [position_3_3] => 4
    [position_3_4] => 7
    [position_3_5] => 4
    [position_3_6] => 10
    [position_4_1] => 6
    [position_4_2] => 2
    [position_4_3] => 2
    [position_4_4] => 1
    [position_4_5] => 7
    [position_4_6] => 6
    [position_5_1] => 3
    [position_5_2] => 7
    [position_5_3] => 8
    [position_5_4] => 10
    [position_5_5] => 3
    [position_5_6] => 2
    [position_6_1] => 8
    [position_6_2] => 2
    [position_6_3] => 10
    [position_6_4] => 2
    [position_6_5] => 10
    [position_6_6] => 9
    [position_7_1] => 6
    [position_7_2] => 10
    [position_7_3] => 4
    [position_7_4] => 8
    [position_7_5] => 1
    [position_7_6] => 5
    [position_8_1] => 2
    [position_8_2] => 7
    [position_8_3] => 4
    [position_8_4] => 7
    [position_8_5] => 9
    [position_8_6] => 13
)

Answer 1

1. Split the list up into a two dimensional array with 6 elements in each 1D array
2. Count the number of times each element appears in the 6 element sub array
3. If there are no ones in the array, make a random element 1
4. If there are 2 or more ones in the array
5. Replace with a random number (other than one) until there is only one one
6. Add the final sub array to a 1 dimensional array
7. Repeat for all the sub arrays in the 2D array

$list_2d = array_chunk($list, 6); 
$final_list = array();
foreach ($list_2d as $array) { 
    $count = array_count_values($array);
    if (!array_key_exists(1, $count))
        $array[mt_rand(0, 5)] = 1;
    else if ($count[1] > 1)
        for ($i = 1; $i <= $count[1] - 1; $i++)
            $array[array_search(1, $array)] = mt_rand(2, 15);
            //Use whatever random number you want here, as long as it's not 1
    $final_list = array_merge($final_list, $array);
}