<?php
$org = array('1', '2', '2', '3', '3', '4', '5', '6');
 
// simple array unique call with sort by string
$new = array_unique($org, SORT_STRING);
 
// output the sorted array
var_dump($new);
echo "";
 
// empty sorted array
$new = array();
var_dump($new);
echo "";
 
// sort with in_array()
for ($i=0; $i < count($org); $i++) {
 
    if (!in_array($org[$i], $new)) {
        $new[] = $org[$i];
    }
}
 
// output the sorted array
var_dump($new);

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