Regular expression for Norwegian numbers

Question

I am trying to write regular expression that is going to match all phone numbers in Norway. That means that number can begin with +47, 0047, 47 or without country code. To achieve that I am using following regular expreession:

Pattern.compile("^((0047)?|(\"+47)?|(47)?)\"d{8}$")

The problem is that it is never matched. I am testing it on the following valid examples:

90909090,   normal number
4790909090, number with country code
+4790909090, country code using +
004790909090, country code using 00

and invalid:

+47909090, without country code or too short number
9090909o,  invalid character
9090909,  too few digits
+4690909090, wrong country code
909090909, too many digits
00474790909090 Trying to fool the regex now

Answer 1

Think you're looking for

(0047|\+47|47)?\d{8} 

which in your Java expression would be:

Pattern.compile("(0047|\\+47|47)?\\d{8}"); 

Answer 2

Sami's answer is nearly correct, but would not be able to identify numbers starting with 0 or 1. Numbers starting with 0 is not allowed and numbers starting with 1 are reserved in Norway (ref). The following should work:

/^(0047|\+47|47)?[2-9]\d{7}$/

In your Java expression:

Pattern.compile("^(0047|\+47|47)?[2-9]\d{7}$")