Identification number is legal, regional validation rules

<?php//birthday is needless to say, the number of the first 6 can be judged by the region//the first 17 digits multiplied by this 17 digit sum  divided by 11, the remainder is the last digit of the ID card (10=2,2=x) except for this two number $arr = [7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, ten, 5, 8, 4, 2]; $result = [0, 1,, 3, 4, 5, 6, 7, 8, 9, ' X ' =>2]; $code = Trim ($_get[' code ']); $count = 0;forea CH ($arr as $key = + $val) {    $num = substr ($code, $key, 1);    $count + = $num * $val;    if ($key = =)        $sex = $num;} $n = intval ($count%); $a = substr ($code,-1, 1); if (!in_array ($n, $result) | | array_flip ($result) [$n]! = Strtoupper ($a) {die    (' ID card not valid ');} if ($sex%2==0)    Echo ' gender female, '; else    echo ' sex male, '; echo ' legal ';? >

Identification number is legal, regional validation rules