Php: remove (different cases) duplicates from array

Question

probably an already discussed topic, but in Php I did not found an answer Is there a simpler way to realize in what follows:

$a = array("hello","hello","Hello","world","worlD");
$p=array();
foreach( $a as $v ){
    $p[strtolower($v)] = "";
}
print_r($p);

keep one single element, in small-case, for the array

Answer 1

You can use array_flip to swap keys and values:

$a = array_flip(array_map('strtolower', $a));

Answer 2

something like:

$p = array_unique(array_map('strtolower', $a));