Question

Just a quick question, I’m writing a regex to allow ONLY letters (so just a words) and the following regex allows spaces, though I have not included them so why are they included?

([a-zA-Z])+

I’ve had to change it to this (pasted from Java):

([a-zA-Z]&&[^\\s])+

To provide context – I’ve tried this and input words with spaces and it still prints true:

public static void main(String[] args) {

        Scanner in = new Scanner(System.in);
        System.out.print("Enter: ");
        String s = in.next();

        if (s.matches("[a-zA-Z]+")) {
            System.out.println("TRUE");
        }

    }

Answer 1

This will always print TRUE as

String s = in.next();

uses the first token input by the user (delimited by space by Scanner).

Better to use:

String s = in.nextLine();