function GetAttributeWithName($attributes,$name){
     foreach($attributes as $attribute):
         if($attribute->attributeName == $name)
              return $attribute;
    endforeach;
    return null;
}
$renk = GetAttributeWithName($json['attributes'] ,"Renk");
print_r($renk);
$beden = GetAttributeWithName($json['attributes'] ,"Beden" );
print_r($beden);