regex

[Randall Twede]

i am just beginning to learn about regex. i need one that allows only positive integers not including 0 {1,2,3,4,...}
it looks like i want something like this
[1-9]\d{0,5}

does that look correct?

[Jeff Verdegan]

Randall Twede wrote:i am just beginning to learn about regex. i need one that allows only positive integers not including 0 {1,2,3,4,...}
it looks like i want something like this
[1-9]\d{0,5}

does that look correct?

Maybe. It looks like it will allow a 1-6 digit integer. I'd test it thought, focusing of course on corner cases.

[fred rosenberger]

if you break that down, I interpret that as this:

any digit from 1-9 ([0-9]), followed by
between 0 and 5 ({0,5}) digits (\d).

So I agree with jeff...this would not match 1234567. It would also not match "1,235", or "0000234". I'm not sure if it would match "+546", or if it would properly reject "-124".

That may be ok, depending on your exact requirements.

[James Boswell]

Randall

Do you have a requirement that limits the number to 6 digits in length?

[Randall Twede]

no, that is just something i found on the web that seemed kind of like what i wanted. i think i am going to just catch the NumberFormatException, and then make sure it is > 0

[James Boswell]

i am going to just catch the NumberFormatException, and then make sure it is > 0

I hope not in that order

[Darryl Burke]

You can use Scanner#hasNextInt() or one of the other, similar, methods and avoid programming via Exception.

[Campbell Ritchie]

It strikes me there is something not quite right about using that regex and exceptions, or that regex and hasNextInt.

[Darryl Burke]

Sorry I wasn't clear. I was suggesting using hasNextInt() instead of regex. I have written code that uses that approach.

    Scanner scanner = new Scanner(GameModel.class.getResourceAsStream("/res/FancyCalls.txt"));
    while (scanner.hasNextLine()) {
      if (scanner.hasNextInt()) {
        int number = scanner.nextInt();
        standardCalls.get(number).add(scanner.nextLine().trim());
      } else {
        // allows intermediate blank or comment lines
        scanner.nextLine();
      }
    }
    scanner.close();

(standardCalls is a Map<Integer, List<String>>)

[Lakshan Dissanayake]

Randall Twede wrote:i am just beginning to learn about regex. i need one that allows only positive integers not including 0 {1,2,3,4,...}
it looks like i want something like this
[1-9]\d{0,5}

does that look correct?

If you need positive integers and it cannot contains 0,1,2,3,4 use ^[^0-4]+$ //like 5,6,7..55,66,77,88,99,56,57... but 50,01,10 not allowed

If you need positive integers and it cannot contains only 0 use ^[1-9][0-9]*$ //like 10,20,99,45... but 01,02.. not allowed

or reply with a post that contain allowed numbers example

Note: ignore comment lines. they are not parts of regex

hope this is useful

for more details refer http://regexone.com/

[Jinu Vijay]

My 2 cents on the topic ... ;)

Regex for number, not containing 0 and is of length 6:

String str = "123234";
System.out.println("String matcher: " + str.matches("[1-9]{6}"));

[Jeff Verdegan]

Jinu Vijay wrote:
Regex for number, not containing 0 and is of length 6:

The OP didn't mean that the digit 0 can't occur in the number. He just meant that the number can't be zero. It has to be a positive number. So 10 would be acceptable, even though it has a 0 digit, because 10 is a positive number.