Multisort array in PHP

We have the following data:

We need to sort it by last name and first name in ascending order. How can we do that in PHP? array_multisort can help us!

More info about array_multisort: https://www.php.net/manual/en/function.array-multisort.php

$data = [
    ['Petrova', 'Sveta'],
    ['Ivanov', 'Oleg'],
    ['Petrova', 'Anna'],
    ['Ivanov', 'Ivan'],
];

$lastNames = array_column($data, 0);
$firstNames = array_column($data, 1);
// This workaround handles cases where the columns used for sorting have equal values.
// Without it, this can lead to a fatal error: Nesting level too deep - recursive dependency?
// Thanks to Yii community https://github.com/yiisoft/yii2/issues/8348
$indexes = range(1, count($data));

array_multisort(
    $lastNames,
    SORT_ASC,
    SORT_STRING,
    $firstNames,
    SORT_ASC,
    SORT_STRING,
    $indexes,
    SORT_ASC,
    SORT_NUMERIC,
    $data
);

Result:

This example is simple, and we haven't used descending order yet. Let's sort last names in ascending order and first names in descending order.

array_multisort(
    $lastNames,
    SORT_ASC,
    SORT_STRING,
    $firstNames,
    SORT_DESC,
    SORT_STRING,
    $indexes,
    SORT_ASC,
    SORT_NUMERIC,
    $data
);

Result:

By the way, we don't have to use array_multisort. Below, I'll show how to sort by multiple fields without this "magic" function (thanks to the Doctrine community).

$data = [
    ['Petrova', 'Sveta'],
    ['Ivanov', 'Oleg'],
    ['Petrova', 'Anna'],
    ['Ivanov', 'Ivan'],
];

$orderings = [
    'lastName' => SORT_ASC,
    'firstName' => SORT_DESC,
];

$orderFn = null;
foreach (array_reverse($orderings) as $field => $ordering) {
    $orderFn = function (array $a, array $b) use ($orderFn, $field, $ordering): int {
        switch ($field) {
            case 'lastName':
                $column = 0;
                break;
                
            case 'firstName':
                $column = 1;
                break;
                
            default:
                return 0;
        }
        
        if ($a[$column] === $b[$column]) {
            if ($orderFn !== null) {
                return $orderFn($a, $b);
            } else {
                return 0;
            }
        }
        
        return ($a[$column] <=> $b[$column]) * ($ordering === SORT_ASC ? 1 : -1);
    };
}

uasort($data, $orderFn);

Result: