<?php

$array = array('aaa', 'bbb', 'aaa', 'ccc', 'ddd', 'ccc', 'eee');

$result = array_unique($array);
print_r($result);

Array
(
    [0] => aaa
    [1] => bbb
    [3] => ccc
    [4] => ddd
    [6] => eee
)