sort an array and rsort an array should give the same order in reverse, the following does not:
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$a = array("0", "1", "01", "2");
sort($a);
while (list ($key, $value) = each ($a)) {
    echo "$key: $value\n";
}
echo "\n";
$a = array("0", "1", "01", "2");
rsort($a);
while (list ($key, $value) = each ($a)) {
    echo "$key: $value\n";
}
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gives the results:
0: 0
1: 01
2: 1
3: 2

0: 2
1: 01
2: 1
3: 0