From: Robert Klemme <shortcutter@...>
Date: 2010-01-11T21:57:07+09:00
Subject: Re: Regex help

2010/1/11 Stefano Crocco <stefano.crocco@alice.it>:
> 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 believe this should rather be \z because \Z allows for a follwing
newline.  So that would be

/\A[a-f\d]{4},[a-f\d]{4}\z/

see http://www.geocities.jp/kosako3/oniguruma/doc/RE.txt

Kind regards

robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/