PHP - Mutidimensional array diff - php

Question

i would like to ask for your help since I'm having difficulty resolving this matter. I had created a function to facilitate on array diff but it does not suffice to my needs. Thanks and more power!
<?php
$arraySession = array(
'sampleA' => array('1', '2', '3'),
'sampleB' => array('1', '2', '3'),
);
$arrayPost = array(
'sampleA' => array('1'),
'sampleB' => array('1','2'),
);
result should be:
array(
'sampleA' => array('2', '3')
'sampleB' => array('3'),
)
my existing function:
public function array_diff_multidimensional($session, $post) {
$result = array();
foreach($session as $sKey => $sValue){
foreach($post as $pKey => $pValue) {
if((string) $sKey == (string) $pKey) {
$result[$sKey] = array_diff($sValue, $pValue);
} else {
$result[$sKey] = $sValue;
}
}
}
return $result;
}
Any help would be much appreciated! Happy coding!

Answer 1

Not my function and not tested by me, but this was one of the first comments at php.net/array_diff (credit goes to thefrox at gmail dot com)
<?php
function multidimensional_array_diff($a1, $a2) {
$r = array();
foreach ($a2 as $key => $second) {
foreach ($a1 as $key => $first) {
if (isset($a2[$key])) {
foreach ($first as $first_value) {
foreach ($second as $second_value) {
if ($first_value == $second_value) {
$true = true;
break;
}
}
if (!isset($true)) {
$r[$key][] = $first_value;
}
unset($true);
}
} else {
$r[$key] = $first;
}
}
}
return $r;
}
?>

Answer 2

This should do it, assuming all keys occur in both arrays:
$diff = array();
foreach ($session as $key => $values) {
$diff[$key] = array_diff($values, $post[$key]);
}
Or, because I'm bored and array_map is underused:
$diff = array_combine(
array_keys($session),
array_map(function ($a, $b) { return array_diff($a, $b); }, $session, $post)
);
(Assumed well ordered arrays though.)

Answer 3

You want something more or less like this:
public function array_diff_multidimensional($arr1, $arr2) {
$answer = array();
foreach($arr1 as $k1 => $v1) {
// is the key present in the second array?
if (!array_key_exists($k1, $arr2)) {
$answer[$k1] = $v1;
continue;
}
// PHP makes all arrays into string "Array", so if both items
// are arrays, recursively test them before the string check
if (is_array($v1) && is_array($arr2[$k1])) {
$answer[$k1] = array_diff_multidimensional($v1, $arr2[$k1]);
continue;
}
// do the array_diff string check
if ((string)$arr1[$k1] === (string)$arr2[$k1]) {
continue;
}
// since both values are not arrays, and they don't match,
// simply add the $arr1 value to match the behavior of array_diff
// in the PHP core
$answer[$k1] = $v1;
}
// done!
return $answer;
}