Arrays are not immutable, that is, they can change after being initialized. You can change the content of an array either by treating it as a map or as a list. Treating it as a map means that you specify the key that you want to override, whereas treating it as a list means appending another element to the end of the array:

<?php
$names = ['Harry', 'Ron', 'Hermione'];
$status = [
    'name' => 'James Potter',
    'status' => 'dead'
];
$names[] = 'Neville';
$status['age'] = 32;
print_r($names, $status);

In the preceding example, the first highlighted line appends the name Neville to the list of names, hence the list will look like ['Harry', 'Ron', 'Hermione', 'Neville']. The second change actually adds a new key-value to the array. You can check the result from your browser by using the function print_r. It does something similar to var_dump, just without the type and size of each value.

If you need to remove an element from the array, instead of adding or updating one, you can use the unset function:

<?php
$status = [
    'name' => 'James Potter',
    'status' => 'dead'
];
unset($status['status']);
print_r ($status);

The new $status array contains the key name only.