如何从切片阵列获取原始密钥？

Question

I have this code :

<?php

$order_list = array ( array ("tangible", 1, 8, 33, 19000),
                      array ("tangible", 1, 9, 8, 19000),
                      array ("tangible", 1, 3, 24, 19000),
                      array ("tangible", 1, 2, 10, NULL),
                      array ("tangible", 1, 17, 11, 28000));

$num = 2;

foreach(array_slice($order_list, $num) as $key => $value) {
    echo $key.'=>'.$value[2].'<br>';
}

?>

and the result is this :

0=>3
1=>2
2=>17

the problem is... $value = 3 has $key = 0, while in the $order_list this value has $key = 2.

so, I'm expecting $key from $order_list based on value sliced. how to do that?

thank you.

Answer 1

....and the manual says: http://us3.php.net/manual/en/function.array-slice.php

The fourth argument, preserve_keys.