regular expressions - phone number and extension

Posted on 2009-04-09
Last Modified: 2012-05-06
We are trying to use regular expressions to check a valid phone number.  We have a pattern but we want to add an option for an extension.
phonePattern = @"\((?<AreaCode>\d{3}) \)?[-\s]? (?<Prefix>\d{3}) [-.] (?<Number>\d{4})";
would this work
phonePattern = @"\((?<AreaCode>\d{3}) \)?[-\s]? (?<Prefix>\d{3}) [-.] (?<Number>\d{4}) x?<ext>\d{10}";
Here are some valid examples for phone numbers
555-123-4567 x1234
555-123-4567 x 1234
555-123-4567 x778942
Question by:tampsystems
  • 2

Expert Comment

ID: 24108489
ok. So, valid examples are:
555-123-4567 x1234
555-123-4567 x 1234
555-123-4567 x778942
e.g. <3 digits><-><3 digits><-><4 digits>#extension Part#<space><x><optional space><4 to 6 digits>

let me put regexp in a simpler form.

this will match all the number formats, mentioned above. A better solution can be made if you know the next character after a number e.g. new line/carriage return.
Hope this helps.

Author Comment

ID: 24116526
I want to be able to support () spaces and dashes
(555) 123 4567
(555) 123-4567
555 123 4567
555 123-4567
555 1234567
555123 4567
And the optional extension number
LVL 13

Expert Comment

ID: 24119510
The following regular expression matches your formats, and the following:

(123) 123-4567 1234
(123) 1234567 1234
(123) 123-4567
(123) 1234567
123-4567 1234
1234567 1234


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LVL 13

Accepted Solution

numberkruncher earned 500 total points
ID: 24119551
Sorry, I just noticed that you wanted an "x" on your extension number.

The below regex matches:

(123) 123-4567 x1234
(123) 1234567 x1234
123-4567 x1234
1234567 x1234

(123) 123-4567 x 1234
(123) 1234567 x 1234
123-4567 x 1234
1234567 x 1234

(123) 123-4567x 1234
(123) 1234567x 1234
123-4567x 1234
1234567x 1234

(123) 123-4567x1234567890
(123) 1234567x1234567890


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