From: Stefano Crocco <stefano.crocco@...>
Date: 2010-01-11T21:50:53+09:00
Subject: Re: Regex help

On Monday 11 January 2010, Chris Lervag wrote:
> |Hi
> |I want to test a string for three properties:
> |1) It is exactly 9 characters long.
> |2) Character number 5 is a comma (',').
> |3) The other characters are either numbers 0-9 or letters a-f.
> |
> |I have been able to do this by a combination of strings methods for 1)
> |and 2), and using a regex match on the string (stripped of the comma)
> |with the following code:
> |myString =~ /([^a-f0-9])/
> |
> |If possible I would like to simplify this by using a more advanced regex
> |match to check all three properties at one time. If this is possible,
> |perhaps one of you regex wizards out there could show me how? :)
> |
> |Best regards,
> |Chris

You could do this with a regexp which matches the following:
* the beginning of the string
* four characters of type a-f or digits
* a comma
* four characters of type a-f or digits
* the end of the string

The regexp is:
 /^[a-f\d]{4},[a-f\d]{4}$/

Note that your string can contain newlines, you must replace ^ and $ with \A 
and \Z respectively.

I hope this helps

Stefano