Online PHP editor | output for LQDb9

@ 2021-07-21T13:26:44Z

<?php

$array = [
    ['id' => 1, 'city' => 'Melbourne', 'user_name' => 'user_1'],
    ['id' => 2, 'city' => 'Melbourne', 'user_name' => 'user_1'],
    ['id' => 3, 'city' => 'Sydney', 'user_name' => 'user_2'],
    ['id' => 4, 'city' => 'Perth', 'user_name' => 'user_3'],
    ['id' => 5, 'city' => 'Perth', 'user_name' => 'user_4']
];

$result = [];
foreach ($array as $row) {
    $result[$row['city']][$row['user_name']] = true;
}
var_export(array_map('count', $result));

Output for 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.4, 8.3.6 - 8.3.26, 8.4.1 - 8.4.13: array ( 'Melbourne' => 1, 'Sydney' => 1, 'Perth' => 2, )
Output for 8.3.5: Warning: PHP Startup: Unable to load dynamic library 'sodium.so' (tried: /usr/lib/php/8.3.5/modules/sodium.so (libsodium.so.23: cannot open shared object file: No such file or directory), /usr/lib/php/8.3.5/modules/sodium.so.so (/usr/lib/php/8.3.5/modules/sodium.so.so: cannot open shared object file: No such file or directory)) in Unknown on line 0 array ( 'Melbourne' => 1, 'Sydney' => 1, 'Perth' => 2, )

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