Regular expresion c# for only digits 0-9 is accepting special character \n sign

Asked Dec 04 '19 at 10:15

Active Dec 04 '19 at 10:35

Viewed 37 times

I want to make regular expresion that will only accept string that are 4 or 6 digit long, and won`t accept any other characters.

I have code like this:

public static bool ValidatePin(string pin)
{
    Regex rx = new Regex(@"(^[0-9]{4}$)|(^[0-9]{6}$)");
    return rx.IsMatch(pin);
}

Prety simple, but when I call:

Console.WriteLine(Kata.ValidatePin("1246\n"));

It returns true, it seems to not omit special character \n. What can I do to solve this problem?

edited Dec 04 '19 at 10:35

fubo

asked Dec 04 '19 at 10:15

Piotr P

1

`$` matches either the end of string or the location before the final newline in a string. Use `\z` to match the real end of string only – Wiktor Stribiżew Dec 04 '19 at 10:16
@WiktorStribiżew Thank you for help. I didn`t know that and spent some time to solve this. Thanks! – Piotr P Dec 04 '19 at 10:18
Yeah, see [my answer](https://stackoverflow.com/a/48832215/3832970) with more details. – Wiktor Stribiżew Dec 04 '19 at 10:19
1

Has been mentioned already to use `\z`. You can further make it a bit shorter: `^\d{4}(?:\d\d)?\z` – bobble bubble Dec 04 '19 at 10:36

0 Answers0