Notice: Undefined offset: 22 in C:\xampp\htdocs\authen.php on line 82

Question

line numbber 82 is the if statement $re_arr is an array containing 25 elements

if ($pass[0]==substr($re_arr[$i],0,1))
{
    $pass1[0]=$re_arr[$i];
    unset($re_arr[$i]);
    $re_arr=array_values($re_arr);
}

what could be done to avoid the notice

Answer 1

Add a check if $re_arr[$i] exists.

if (!empty($re_arr[$i]) && $pass[0]==substr($re_arr[$i],0,1))
{
    $pass1[0]=$re_arr[$i];
    unset($re_arr[$i]);
    $re_arr=array_values($re_arr);
}