Online PHP editor | output for 4KdLs

@ 2021-08-27T17:29:07Z

<?php declare(strict_types=1);

/**
 * https://stackoverflow.com/a/68884808/367456
 */

$arr1 = [
    "databases" => [
        0 => [
            "id" => 1,
            "name" => "DB1",
            "slug" => "db1",
            "url" => "https://www.db1.org",
        ],
    ],
];

$arr2 = [
    "databases" => [
        0 => [
            "id" => 5,
            "name" => "DB2",
            "slug" => "db2",
            "url" => "https://www.db2.com",
        ],
    ],
];

/**
 * recursively go over two (optional) arrays old and new
 * while merging them.
 *
 * array values are then taken as:
 *
 *     ['old' => $old, 'new' => $new].
 *
 * @param array|null $old
 * @param array|null $new
 * @return array
 */
function old_and_new(array $old = null, array $new = null): array
{
    $pair = get_defined_vars();
    $map =
        static fn(callable $map, array $arrays): array => in_array(true, array_map('is_array', $arrays), true)
        && ($parameter = array_combine($k = array_keys($arrays), $k))
        && ($keys = array_keys(array_flip(array_merge(...array_values(array_map('array_keys', array_filter($arrays, 'is_array'))))))
        )
            ? array_map(
                static fn($key) => $map($map, array_map(static fn($p) => $arrays[$p][$key] ?? null, $parameter)),
                array_combine($keys, $keys)
            )
            : $arrays;

    return $map($map, $pair);
}

print_r(old_and_new(new: $arr2));

Output for 7.4.0 - 7.4.33: Parse error: syntax error, unexpected ':' in /in/4KdLs on line 58
Process exited with code 255.
Output for 8.0.0 - 8.0.30, 8.1.0 - 8.1.34, 8.2.0 - 8.2.34, 8.3.0 - 8.3.4, 8.3.6 - 8.3.33: Array ( [databases] => Array ( [0] => Array ( [id] => Array ( [old] => [new] => 5 ) [name] => Array ( [old] => [new] => DB2 ) [slug] => Array ( [old] => [new] => db2 ) [url] => Array ( [old] => [new] => https://www.db2.com ) ) ) )
Output for 7.3.0 - 7.3.33: Parse error: syntax error, unexpected 'fn' (T_STRING), expecting :: (T_PAAMAYIM_NEKUDOTAYIM) in /in/4KdLs on line 45
Process exited with code 255.
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 ( [databases] => Array ( [0] => Array ( [id] => Array ( [old] => [new] => 5 ) [name] => Array ( [old] => [new] => DB2 ) [slug] => Array ( [old] => [new] => db2 ) [url] => Array ( [old] => [new] => https://www.db2.com ) ) ) )
Output for 8.4.1 - 8.4.26, 8.5.0 - 8.5.9: Deprecated: old_and_new(): Implicitly marking parameter $old as nullable is deprecated, the explicit nullable type must be used instead in /in/4KdLs on line 41 Deprecated: old_and_new(): Implicitly marking parameter $new as nullable is deprecated, the explicit nullable type must be used instead in /in/4KdLs on line 41 Array ( [databases] => Array ( [0] => Array ( [id] => Array ( [old] => [new] => 5 ) [name] => Array ( [old] => [new] => DB2 ) [slug] => Array ( [old] => [new] => db2 ) [url] => Array ( [old] => [new] => https://www.db2.com ) ) ) )

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