The best way to copy element data with object protection to an array

Question

* Edited my question after identifying the underscore problem.
Many thanks to choz who helped diagnose the problem *

* Description * I have a class with two members that respectively store data about albums and photos. In the constructor, I populate them with data extracted from the database query. These queries return an object with an array that is a protected member of the object.

I tried to add a new key and value to an object containing an associative array, mistakenly treating it as a simple array. This new key and value have not been set. Presumably because the element of the array of objects is protected. See Dump var below, where Object dump begins: ["Data": protection]. This is problem? And if so, what is the best way to create my own copies that I can freely manipulate?

/****** Class  Memebers ********/ 
//Object with array of associative album arrays.
//Each inner album array is defined by unique key ='albumID'.
private $member_albums; 


//array of objects holding associative photo arrays.
//Each inner photo array is defined by unique key ='albumID'.
private $member_photos;     

This is the method used to add the key and value -

/*
* For each photo in each album, we will add a new key and value.  
* key = 'img_url', value is an array with structure of 
* ['S']['{url pointing to this photo in storage}'] where 'S' is the 
* key (representing a string value) and value is the url string.  
*/
private function add_Photo_Url_To_Photos_Data_Array(){

  // If data was retrieved from DB without errors
  // because query fail returns false.
  if( $this->member_albums && $this->member_photos){

    // If user has albums - because 'Count' is always 0 or
    // greater, representing the number of inner arrays
    if($this->member_albums['Count'] > 0 ){ 

        // For number of albums
        foreach ($this->member_albums['Items'] as $albumArr) {

            // Current album ID 
            $curr_AlbumId = $albumArr['albumID']['S'];                  

            // If current album contains photos
            if( $this->member_photos[$curr_AlbumId]['Count'] > 0){                                              

                // For each photo in this album
                foreach( $this->member_photos[$curr_AlbumId]['Items'] as &$photosArr) {

                    // method that creates a url from photo data- returns string url                                                                                    
                    $url = $this->build_Photo_Url($photosArr, $curr_AlbumId);                                                       

                    // Insert new key = 'img_url' and value into the array.                                                                                 
                    // new value is itself an array with key ['S']  
                    // signifying a string and value $url   
                    $photosArr['img_url'] = array('S' =>
                    $url);

                    // this echo shows key and value were added
                    // correctly into $photosArr
                    echo ' <br>Img URL = ' . $photosArr['img_url']['S'];                                                            
                }                   
            }                                   
        }
    }
}

But if I try and echo "img_url" from the array element $ this-> member_photos, it does not exist.

Thanks.

*** EDIT 3 **** Adding var_dump ($ this-> member_albums) and var_dump ($ this-> member_photos)

var_dump ($ this-> member_albums)

object(Guzzle\Service\Resource\Model)#88 (2) { 
["structure":protected]=> NULL ["data":protected]=> array(3) { 
    ["Count"]=> int(2) 
    ["Items"]=> array(2) { 
        [0]=> array(7) { 
            ["PlaceLong"]=> array(1) { ["N"]=> string(1) "0" } 
            ["AlbumId"]=> array(1) { ["S"]=> string(7) "album_1" } 
            ["Title"]=> array(1) { ["S"]=> string(5) "Test1" } 
            ["UserId"]=> array(1) { ["S"]=> string(36) "810725E5-D235-43F7-AA50-4CCDACD6AB36" } 
            ["Year"]=> array(1) { ["N"]=> string(1) "0" } 
            ["PlaceLat"]=> array(1) { ["N"]=> string(1) "0" } 
            ["Timestamp"]=> array(1) { ["N"]=> string(16) "472572846.470462" } 
        }

var_dump ($ this-> member_photos)

array(2) { 
["album_1"]=> object(Guzzle\Service\Resource\Model)#89 (2) { 
["structure":protected]=> NULL ["data":protected]=> array(3) { 
    ["Count"]=> int(5) 
    ["Items"]=> array(5) { 
        [0]=> array(8) { 
            ["ShotId"]=> array(1) { ["S"]=> string(6) "Photo2" } 
            ["AlbumId"]=> array(1) { ["S"]=> string(7) "album_1" } 
            ["UserId"]=> array(1) { ["S"]=> string(16) "1111-11111-11111" } 
            ["Year"]=> array(1) { ["N"]=> string(1) "0" } 
            ["Discovery"]=> array(1) { ["N"]=> string(1) "0" } 
            ["Timpstamp"]=> array(1) { ["N"]=> string(14) "472572840.3845" } 
            ["ExtractedPhotoId"]=> array(1) { ["S"]=> string(32) "Photo2_0-0-746-0-0-1000-746-1000" } 
            ["ManualEdit"]=> array(1) { ["N"]=> string(1) "0" } 
        }

Answer 1

, Model, , toArray(), protected.

: http://docs.aws.amazon.com/aws-sdk-php/v2/guide/feature-models.html

var_dump(get_class_methods($this->member_albums)));, , . , toArray(), , , .

var_dump(), $clearArr = $this->member_albums->toArray(); print_r/var_dump $clearArr, .