php how to push (accumulating) multidimensional array

Question

Please, help with multidimensional array push. Please, see the code and comments below. The push is giving an error. The assigning is giving the last row only.

if (!isset($_SESSION['page_qstn_answer'])) {
$_SESSION['page_qstn_answer'] = array("page" => array(), "qstn" => array(), "answer" => array()
}
if (!isset($temp)) {
$temp = array("page" => array(), "qstn" => array(), "answer" => array() );
}
while($question = mysqli_fetch_assoc($question_set) ) {
if(isset($question['position']) ){
$post_qstn = $question['position'];
If(isset($_POST[$qstn]) ) {
//printing all rows from db correctly as below
//echo "Question ".$qstn." - selected answer  ".$answer . " on page ".$page ."<br />";
if (isset($temp) ){
$temp = array ("page"=>$page, "qstn"=>$qstn,"answer"=> $answer);}
//show a one by one array rows correctly but $temp has a one row at a time that is Ok
//print_r($temp);
// Try to accumulate $temp into $_Session array. Push is giving an error
//$_SESSION['pages_qstn_answers'] = array_push($_SESSION['pages_qstn_answers'], $temp);
// No error but no accumulation as foreach as below shows the only one last row.
$_SESSION['pages_qstn_answers'] = $temp;
}
foreach ($_SESSION['pages_qstn_answers'] as $key => $value) {
echo "$key = $value\n";}

Answer 1

I used a function that I found on the website to delete all previously added the same questions before accumulating the $temp entries into the final array as there should be the only one question with a one answer. It seems a working. If somebody could see some shortcomings there please advise. Thanks

remove_elm($_SESSION['pages_qstn_answers'], "qstn", $qstn, TRUE);
$_SESSION['pages_qstn_answers'][] = $temp;
function remove_elm($arr, $key, $val, $within = FALSE) {
foreach ($arr as $i => $array)
if ($within && stripos($array[$key], $val) !== FALSE && (gettype($val) === gettype($array[$key])))
unset($arr[$i]);
elseif ($array[$key] === $val)
unset($arr[$i]);
return array_values($arr);
}

Answer 2

You have a misunderstanding of how array_push() works. It does not return the array, it just appends whatever value you have to it. So when you do:

$_SESSION['pages_qstn_answers'] = array_push($_SESSION['pages_qstn_answers'], $temp);

The right hand side of the equation simply returns an integer containing the number of elements in the new array. So say you now have 5 elements in your array, you are essentially doing

$_SESSION['pages_qstn_answers'] = 5;

Instead just do:

array_push($_SESSION['pages_qstn_answers'], $temp);

or since you're only appending one value I would stick with:

$_SESSION['pages_qstn_answers'][] = $temp;