array_diff() returns empty array

Question

I have the following two arrays:

array(1) { [0]=> array(2) { ["foo"]=> string(4) "Test" ["bar"]=> string(18) "Test" } } 

array(3) { [0]=> array(2) { ["foo"]=> string(3) "295" ["bar"]=> string(1) "9" } [1]=> array(2) { ["foo"]=> string(7) something" ["bar"]=> string(17) "something else" } [2]=> array(2) { ["foo"]=> string(5) "Test2" ["bar"]=> string(19) "Test2" } }

array_diff($arr1, $arr2); returns empty array, where $arr1 and $arr2 are accordingly first and second arrays var dumped here.

Why is that so?

The code is:

$arr1 = array(
    array('foo' => 'Test', 'bar' => 'Test')
);

$arr2 = array(
      array('foo' => '295', 'bar' => '9'),
      array('foo' => 'something', 'bar' => 'else'),
      array('foo' => 'Test2', 'bar' => 'Test2')
);

var_dump(array_diff($arr1, $arr2));

`array_diff` - *function only checks one dimension of a n-dimensional array.* — Sougata Bose, Sep 23 '15 at 09:44
http://stackoverflow.com/questions/11821680/array-diff-with-multidimensional-arrays — 131, Sep 23 '15 at 09:45
The expected output would be `$arrOutput = array( array('foo' => 'Test', 'bar' => 'Test') );`, as it is not present in the second array — khernik, Sep 23 '15 at 09:46
It's because you are trying to use `array_diff()` on a one diminsional array. you need to use the link above if you want to see the answered question for multidiminsional array — 131, Sep 23 '15 at 09:47
Please [edit] your comment answer(s) into your question as well. — Jan Doggen, Sep 23 '15 at 09:49
An alternative can be `print_r(array_intersect($arr1, array_merge($arr1,$arr2)));` — Narendrasingh Sisodia, Sep 23 '15 at 09:54

score 0 · Answer 1 · answered Sep 23 '15 at 09:55

This function only checks one dimension of a n-dimensional array.

You can try some other way like -

$op= [];
foreach($arr2 as $array) {
   $check = array_diff($arr1[0], $array);
   $op[]= $check;
}
$op= array_filter($op);

$op = (count($op) === count($arr2)) ? $arr1 : null;

Check it here

score 0 · Answer 2 · answered Sep 23 '15 at 10:05

You can use this

$result = check_diff_multi($arr1, $arr2);
print '<pre>';
print_r($result);
print '</pre>';

function check_diff_multi($array1, $array2){
    $result = array();
    foreach($array1 as $key => $val) {
         if(isset($array2[$key])){
           if(is_array($val) && $array2[$key]){
               $result[$key] = check_diff_multi($val, $array2[$key]);
           }
       } else {
           $result[$key] = $val;
       }
    }

return $result;

}

array_diff() returns empty array

2 Answers2