What are potential pitfalls to avoid when working with multidimensional arrays and objects in PHP?

One potential pitfall when working with multidimensional arrays and objects in PHP is not properly checking if a key or property exists before trying to access it. This can result in errors or unexpected behavior if the key or property does not exist in the array or object. To avoid this, you can use functions like isset() or property_exists() to check if a key or property exists before attempting to access it.

// Check if a key exists in a multidimensional array
if(isset($array['key']['nested_key'])) {
    // Access the value if the key exists
    $value = $array['key']['nested_key'];
}

// Check if a property exists in an object
if(property_exists($object, 'property')) {
    // Access the property if it exists
    $value = $object->property;
}