Inclusive Taiwan Identification Number Validation

import math
import re

ID_REGEX = '^[A-Z]{1}[1-2A-D8-9]{1}[0-9]{8}$';
ID_LETTERS = 'ABCDEFGHJKLMNPQRSTUVXYWZIO';

def isValid(id_no):
    id_no = id_no.upper()
    regex = re.compile(ID_REGEX)
    if (regex.match(id_no) is None):
        return False

    letterIndex = ID_LETTERS.index(id_no[0])
    checksum = math.floor(letterIndex / 10 + 1) + (letterIndex * 9)

    # Legacy ARC
    if (re.match('[A-Z]', id_no[1])):
        checksum = checksum + (ID_LETTERS.index(id_no[1]) % 10) * 8;
    else:
        checksum = checksum + int(id_no[1]) * 8

    for position in range(2, 9):
        checksum = checksum + (9 - position) * int(id_no[position])

    checksum = checksum + int(id_no[9])

    if (checksum % 10) == 0:
        return True
    else:
        return False

<?php

define("ID_REGEX", '/^[A-Z]{1}[1-2A-D8-9]{1}[0-9]{8}$/');
define("ID_LETTERS", 'ABCDEFGHJKLMNPQRSTUVXYWZIO');


function isValid($id_no)
{

  $id_no = strtoupper($id_no);
  if (preg_match(ID_REGEX, $id_no) != 1)
  {
    return false;
  }

  $letterIndex = strpos(ID_LETTERS, $id_no[0]);
  $checksum = floor($letterIndex / 10 + 1) + ($letterIndex * 9);

  // Legacy ARC
  if (preg_match('/[A-Z]/', $id_no[1]) == 1)
  {
    $checksum += (strpos(ID_LETTERS, $id_no[1]) % 10) * 8;
  } else {
    $checksum += intval($id_no[1]) * 8;
  }
  
  for ($i = 2 ; $i < 9 ; $i++) { 
    $checksum += (9 - $i) * intval($id_no[$i]);
  }
  $checksum += intval($id_no[9]);

  if (($checksum % 10) == 0){
    return true;
  } else {
    return false;
  }

}
?>

Coming soon

public class ValidId {

  static final String ID_REGEX = "^[A-Z]{1}[1-2A-D8-9]{1}[0-9]{8}$";
  static final String ID_LETTERS = "ABCDEFGHJKLMNPQRSTUVXYWZIO";

  public static boolean isValid(String idNo) {
    idNo = idNo.toUpperCase();

    if (!idNo.matches(ID_REGEX)) {
      return false;
    }

    int letterIndex = ID_LETTERS.indexOf(idNo.charAt(0));
    int checksum = (int) Math.floor(letterIndex / 10 + 1) + (letterIndex * 9);
  
    // Legacy ARC
    if (Character.isLetter(idNo.charAt(1))) {
      checksum += (ID_LETTERS.indexOf(idNo.charAt(1)) % 10) * 8;
    } else {
      checksum += Character.getNumericValue(idNo.charAt(1)) * 8;
    }

    for (int i = 2 ; i < 9 ; i++) {
      checksum += (9 - i) * Character.getNumericValue(idNo.charAt(i));
    }
    checksum += Character.getNumericValue(idNo.charAt(9));
 
    return checksum % 10 == 0;
  }
}