xml - PHP array_unique not behaving as expected -

i have little php script running.
puts content of xml file , assigns variable.
create array containing xml tags , values want use, using parse array function lib_parse.php:

function parse_array($string, $beg_tag, $close_tag) {     preg_match_all("($beg_tag(.*)$close_tag)siu", $string, $matching_data);         //preg_match_all("($beg_tag(.*)($beg_tag(.*)$close_tag)+(.*)$close_tag)siu", $string, $matching_data);     return $matching_data[0]; } 

this works well.

but remove duplicates huge array.
have done through excel , know should give me 3945 xml tags , values.
when run array through array_unique, returns me array 3945 lines 400 of them contain xml tags , values want, others blank lines.

$value = file_get_contents("myxmlfile.xml"); $array = parse_array($value, "<marker", "/>"); $clean_array = array_unique($array); 

i use loop put values of array xml file.

any ideas?

sorry length of this.