Problem with regular expressions i .NET

[Arne]

Hi,

I'm trying to recognise phone numbers on the following format using
regular expressions: +47 123 45 678

This should be recognised by the following regular expression:
+47 \d{3} \d{2} \d{3} but it's not.

This regular expression: +47 \d{2} \d{2} \d{2} \d{2} DOES recognise
the following phone number: +47 12 34 56 78

Any ideas why the first doesn't work?
I'm using C#.

Thanks in advance, regards,
Lars D.

 

[Fakher Halim]

Arne,

The "+ " in a regular expression is treated as a quantifier; means one or more occurrence of the preceding character.

Since there is no preceding character before "+", it should give you a run time error of bad quantifier.

Regex re=new Regex(@"+47 \d{2} \d{2} \d{2} \d{2}");
if(re.IsMatch("+47 12 34 56 78"))
Console.WriteLine("Matched");

If you want the + character to be recognized literally, just escape it with a backslash.

This should run

Regex re=new Regex(@"\+47 \d{2} \d{2} \d{2} \d{2}");
if(re.IsMatch("+47 12 34 56 78"))
Console.WriteLine("Matched");

Thanks,

Fakher Halim
Technical Architect, TPG

 

[Arne]

Sorry, that was a typo in my original post. I actually have escaped
the "+" character. I get no error messages, I just can't get any
matches for phone numbers on the following format: +47 123 45 678
Thank you for your reply.

 

[Fakher Halim]

Arne,
The following code prints "Matched" on my console. Doesn't it work on yours?
Would you copy pasted the actual code that is failing?

Regex re=new Regex(@"\+47 \d{2} \d{2} \d{2} \d{2}");
if(re.IsMatch("+47 12 34 56 78"))
Console.WriteLine("Matched");

Fakher Halim

 

[Fakher Halim]

For "+47 123 45 678", the "\+47 \d{2} \d{2} \d{2} \d{2}" would not match. if
you want to allow 2 to three digit in some place, use "\d{2,3}" instead of
\d{2}.
Fakher Halim