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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!

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4 Answers

up vote 1 down vote

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;
}
?>
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thanks dtbarne, im gonna try this. –  Jay Milagroso May 17 '11 at 5:17
 
Looks like it can only handle one array deep. –  alex May 17 '11 at 5:24
 
hi dtbarne, using this function doesnt procure expected results. try: $arraySession = array( 'sampleA' => array('1', '2', '3'), 'sampleB' => array('1', '2', '3'), ); $arrayPost = array( 'sampleA' => array('1','2','3'), 'sampleB' => array('1',), ); –  Jay Milagroso May 17 '11 at 5:28
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up vote 1 down vote

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.)

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Please clarify the givens and edge-cases in your question. I'm not even sure if you mean "two-dimensional" or real "multi-dimensional". –  deceze May 17 '11 at 5:37
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up vote 1 down vote

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;
}
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thanks Luke, im gonna try this. –  Jay Milagroso May 17 '11 at 5:19
 
i tried using this and wont procure expected results. try: $arraySession = array( 'sampleA' => array('1', '2', '3'), 'sampleB' => array('1', '2', '3'), ); $arrayPost = array( 'sampleA' => array('1','2','3'), 'sampleB' => array('1',), ); –  Jay Milagroso May 17 '11 at 5:29
 
Whups. Since any array typecast to a string is simply "Array" (I forgot about this from my PHP days), all arrays were considered equal. I moved the array check to before the string check, and now it does work (and works with n-dimensional arrays, to boot). –  Luke Sneeringer May 17 '11 at 14:55
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up vote 0 down vote accepted

i already got it. i just utilized the use of foreach. thanks to all who shared their ideas! happy coding!

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