PHP - Mutidimensional array diff

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 need

Answer 1

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;
}

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

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;
}
?>