Group array by key

array_group.php

<?php

declare(strict_types=1);

$items = [
    ["id" => 20, "name" => "chimpanzee"],
    ["id" => 40, "name" => "meeting"],
    ["id" => 20, "name" => "dynasty"],
    ["id" => 50, "name" => "chocolate"],
    ["id" => 10, "name" => "bananas"],
    ["id" => 50, "name" => "fantasy"],
    ["id" => 50, "name" => "football"],
];

$columnName = "id";
$columnValues = array_values(array_unique(array_column($items, $columnName)));

$result = array_combine(
    $columnValues,
    array_map(
        static fn(int $columnValue) => array_values(
            array_filter(
                $items,
                static fn(array $item) => $item[$columnName] === $columnValue
            )
        ),
        $columnValues
    )
);

ksort($result, SORT_NUMERIC);