array_group_by.php

<?php

function array_group_by(array $array, callable $key_selector)
{
    $result = [];

    foreach ($array as $values) {
        $key = call_user_func($key_selector, $values);
        $result[$key][] = $values;
    }

    return $result;
}

// Example

$data = array(
    [1, "A", "AA"],
    [1, "A", "BB"],
    [1, "A", "CC"],
    [2, "B", "AA"],
    [2, "B", "BB"],
    [3, "C", "AA"],
);

$grouped = array_group_by($data, function($row) { return $row[0]; });

print_r($grouped);