<?php
$input = array("a" => "green", "red", "b" => "green", "blue", "red");
$result = array_unique($input);
print_r($result);
?>
Array
(
[a] => green
[0] => red
[1] => blue
)<?php
// app.php
$data = [19, 21, 19, 21, 46, 21, 29, 21, 18];
print_r(array_unique($data));