Given the following array:

<?php
$myArr = array( 'joe' => 'bob', "0" => 'briggs', 'whatever', 'whereever');
echo '<pre>' . print_r( $myArr, TRUE ) . '</pre>';
?>

Array
(
[joe] => bob
[0] => briggs
[1] => whatever
[2] => whereever
)

"joe" and "0" are keys that I created whereas the key "1" and "2" are
keys assigned by PHP when the array was created. When iterating
through an array, is there a way to determine which were generated by
PHP? I can't rely on whether or not the key is an integer because
it's quite possible that such a key was user generated. I've gone
through the docs and based on what I've read, I don't think something
like this is possible but I'm hoping that's not the case.

Any pointers?

thnx,
Christoph