add to array if it isn't there already

Question

How do I add elements to an array only if they aren\'t in there already? I have the following:

$a=array();
// organize the array
foreach($array as $k=>$v)         


        

Answer 1

If you don't care about the ordering of the keys, you could do the following:

$array = YOUR_ARRAY
$unique = array();
foreach ($array as $a) {
    $unique[$a] = $a;
}

Answer 2

you can try using "in_array":

function insert_value($value, &$_arr) {
    if (!in_array($value, $_arr)) {
        $_arr[] = $value;
    }
}