Sortering af et dobbelt array?

function cmp($a, $b) {
    return strcmp($a[0], $b[0]);
}

usort($arr, "cmp");

<?php
$product = array(array(), array(), array(), array(), array());
$product[0][0] = "Æbler";
$product[0][1] = "10";

$product[1][0] = "Pærer";
$product[1][1] = "7";

$product[2][0] = "Æbler";
$product[2][1] = "5";

$product[3][0] = "Gulerødder";
$product[3][1] = "887";

$product[4][0] = "Agurk";
$product[4][1] = "3";

$product[5][0] = "Agurk";
$product[5][1] = "117";

foreach($product as $p) {
    echo $p[0] . ' ' . $p[1] . "\r\n";
}

$map = array();
$aggr = array();
foreach($product as $p) {
    if(array_key_exists($p[0], $map)) {
        $aggr[$map[$p[0]]][1] += $p[1];
       
    } else {
        $map[$p[0]] = count($aggr);
        $aggr[] = $p;
    }
}

foreach($aggr as $p) {
    echo $p[0] . ' ' . $p[1] . "\r\n";
}
?>