How to correctly compare two arrays for equality in PHP? Exploring the nuances

Hello everyone! I'm a beginner in PHP and I've encountered a task that has stumped me. I need to check if two arrays are equal. At first glance it seems simple, but I've already racked my brain.\n\nI have two arrays with user data. The first array comes from the database, the second from a form on the site. I want to understand if the data has changed so as not to send unnecessary update requests.\n\nHere's an example code:\n```php\n$old_data = ['name' => 'Ivan', 'age' => 30, 'city' => 'Moscow'];\n$new_data = ['name' => 'Ivan', 'age' => 30, 'city' => 'Moscow'];\n\nif ($old_data == $new_data) {\n echo "Arrays are equal";\n} else {\n echo "Arrays are not equal";\n}\n```\n\nThis code works and outputs "Arrays are equal". But I noticed that if the order of elements is different, `==` also considers them equal:\n```php\n$a =