Flutter String formatter-CodePudding

how to check if strings is voucher

4 letters separated by (-) then 4 letters separated by (-) then 4 letters separated by (-) 4 letters separated by (-)

ex: ABCD-ABCD-ABCD-ABCD

CodePudding user response：

You could use a regular expression for that, something like this:

void main() {
  String voucher = 'ABCD-ABCD-ABCD-ABCD';
  RegExp voucherRegex = RegExp(r'^[A-Z]{4}-[A-Z]{4}-[A-Z]{4}-[A-Z]{4}$');

  if (voucherRegex.hasMatch(voucher)) {
    print('The string is a voucher');
  } else {
    print('The string is not a voucher');
  }
}

this regular expression is only for upper case letters, don't know if can be lower case in your use case

CodePudding user response：

You can use this method to achieve it :

  bool isVoucher(String text, [String separator = "-"]) {
    final wordsList =
        text.split(separator).where((word) => word.length == 4).toList();
    return wordsList.length == 4;
  }


print(isVoucher("ABCD-ABCD-ABCD-ABCD")); // true
print(isVoucher("ABCD-ABCD-ABCDs")); // false