Need a regex to match a variable length string of numbers that can't be all zeros

Question

I need to validate an input on a form. I'm expecting the input to be a number between 1 to 19 digits. The input can also start with zeros. However, I want to validate that they are not all zeros. I've got a regex that will ensure that the input is numeric and between 1 and 19 numbers.

^\d[1,19]$

But I can't figure out how to include a check that the entire string is not all zeros. I tried this

^(![0]{1,19})(\d[1,19])$

but it fails on 0000000000000000001 because it's allowing a variable number of zeros.

How do I check that the entire string is NOT zeros?

Thanks.

I'm trying to do this in a ASP.NET RegularExpressionValidator so I was hoping for a single expression. I have other options, so I'm not out of luck if this can't be done.

Answer 1

^(?!0+$)\d{1,19}$

Answer 2

Just do a negative lookahead:

(?!^0+$)(^\d{1,19})

This works fine in Perl.

Answer 3

(?!0+$) is a lookahead directive. The ?! is the negative lookahead command to search for 1 or more 0's to the end of the string. If that matches, then the characters are consumed, leaving the regular digit search of \d{1,19}.

Boost Perl Regexp has a good discussion of perl regexp as recognized by Boost.

Answer 4

you don't need RegEx for that

            ulong test;
        string number = "1234567890123456789";
        if (ulong.TryParse(number, out test) && (test < 9999999999999999999ul) && (test > 0))
            Console.WriteLine(test);