从数组中，使用PHP基于键值对项目进行分组

Question

I've this multidimensional array in PHP:

Array
(
    [0] => Array
        (
            [continent] => Europa
            [country] => France
            [capital] => Paris
        )

    [1] => Array
        (
            [continent] => Europa
            [country] => Spain
            [capital] => Madrid
        )
    [2] => Array
        (
            [continent] => Asia
            [country] => Russia
            [capital] => Moscow
        )
)

How can I group countries depending the continent ?

So countries in the same continent should be group together.

The desired output should be:

Array
(
    [Europa] => Array
        (
            [country] => France
            [capital] => Paris
        ),
        (
            [country] => Spain
            [capital] => Madrid
        )
    [Asia] => Array
        (
            [country] => Russia
            [capital] => Moscow
        )
)

How it is possible with PHP please ?

Thanks.

Answer 1

$groupByContinent = function(array $list) {
    return array_reduce($list, function($grouped, $item) {
        $grouped[$item['continent']][] = $item;
        return $grouped;
    }, []);
};

$groupedByContinent = $groupByContinent($data);

https://3v4l.org/s6X1c

Or:

$groupByProperty = function(array $list, string $property) {
    return array_reduce($list, function($grouped, $item) use(&$property) {
        $grouped[$item[$property]][] = $item;
        return $grouped;
    }, []);
};

$groupedByContinent = $groupByProperty($data, 'continent');

https://3v4l.org/Be3HL