duplicate

gistfile1.txt

<?php
//@link http://codepad.viper-7.com/GOutvO
	$data = array(1,2,3,1,3,99,99,4,5,3,2,1,99); 
	$duplicate = array(); 
	foreach ($data as $a) {
		array_pop($data);
		foreach($data as $b){
			if ($a == $b && !in_array($a,$duplicate)){
				$duplicate[] = $b;
				echo "duplicate {$a} <br />\r\n";
			}
		}
	}
?>