Email Duplicate Removal More Than 20k not working

I've created a script to remove duplicate emails and it works perfectly up to about 20k. After that it just stops with no error code. I'm baffled. I've increased the max_execution_time to 2 hours even though this script just takes a few minutes.

<?PHP
function validElement($element) {
    return strlen($element) > 1;
}

function in_iarray($str, $a){
foreach($a as $v){
if(strcasecmp($str, $v)==0){return true;}
}
return false;
}

remove_duplicates();
}
//Remove more duplicates from list
function array_iunique($a){
$n = array();
foreach($a as $k=>$v){
if(!in_iarray($v, $n)){
echo $v;
$n[$k]=$v;}
}
return $n;
}

//Remove duplicates from list
function remove_duplicates() {

$p = 0;
while ($p != 1) {
   
$rawemaillist = array_values(array_filter($rawemaillist, "validElement"));
$p = 1;
}
$initial = count($rawemaillist);
$k = 0;
while ($k != 1) {
$rawemaillist = array_iunique($rawemaillist);
$k = 1;
}
?>

The script works fine - but only up to around 20 k - which leads me to believe its a server setting issue. Is there something in the php.ini file I should or otherwise a setting that I should be looking at to change???

its probably memory, turn error reporting on

code:

error_reporting(E_ALL);

why not use array_unique then filter the emails for valid emails ??

thank you for the response. That's exactly what i'm going to do. I'm trying to convert all the values within the array to lowercase first before using 'array_unique'.

how about

$a = array("TEST", "test2", "test3");
$b = array_map("strtolower", $a);
print_r($b);

MadTechie - you're the man - that' s what I needed to know. Thankyou.