Optimizing array merge operation

Question

I would appreciate any help, given.

I have 7 separate arrays with approx. 90,000 numbers in each array (let\'s call them arrays1-arrays7). There are no duplicate num

Answer 1

I suggest replacing

foreach($result as $key => $val)
{
    if($result[$key]==3)
    {
    fwrite($fp_lines, $key."\r\n");
    }
}

With something like

$res = array_keys(array_filter($result, function($val){return $val == 3;}));
fwrite($fp_lines, implode("\r\n", $res));