Group a multidimensional array by key value?

Question

I have a multidimensional array, I'm trying to group an array based on a key value.

So, I'm trying to group them by key, but I'm not going to group an array based on key values.

Below is the original array

 Array
    (
        [0] => Array
            (
                [User] => Array
                    (
                        [id] => 2
                        [feature] => AddUser
                        [feature_level] => 1
                        [parent_feature] => 1
                    )

            )

        [1] => Array
            (
                [User] => Array
                    (
                        [id] => 3
                        [feature] => EditUser
                        [feature_level] => 1
                        [parent_feature] => 1
                    )

            )

        [2] => Array
            (
                [Candidate] => Array
                    (
                        [id] => 5
                        [feature] => AddCandidate
                        [feature_level] => 1
                        [parent_feature] => 4
                    )

            )

        [3] => Array
            (
                [Candidate] => Array
                    (
                        [id] => 6
                        [feature] => EditCandidate
                        [feature_level] => 1
                        [parent_feature] => 4
                    )

            )

    )

I need

   Array (

   [User] => Array (
          [0] => Array (
                    [id] => 2
                    [feature] => AddUser
                    [feature_level] => 1
                    [parent_feature] => 1
                    )
          [1] => Array (
                    [id] => 3
                    [feature] => EditUser
                    [feature_level] => 1
                    [parent_feature] => 1
                    )
          )

   [Candidate] => Array (
          [0] => Array (
                    [id] => 5
                    [feature] => AddCandidate
                    [feature_level] => 1
                    [parent_feature] => 4
                 )

          [1] => Array (
                    [id] => 5
                    [feature] => EditCandidate
                    [feature_level] => 1
                    [parent_feature] => 4
                 )
          )

)

Answer 1

Here is a solution with a demo. I can help you:

// $myArr is your origional array.
$result_arr = [];

array_walk($myArr,function($v,$k) use (&$result_arr){
   $result_arr[key($v)][] = $v[key($v)]; 
});

print_r($result_arr);

Click here for a demo.

Answer 2

If your initial array is called $source, this should do it:

$result =[]; //final array
foreach($source as $data){
    $type = key($data); //eg: 'Candidate' or 'User'
    if(!isset($result[$type])) $result[$type]=[];
    $result[$type][] = reset($data);
}

Demo here