From: Stefano Crocco <stefano.crocco@...>
Date: 2008-06-24T16:46:00+09:00
Subject: Re: Regex extracting certain characters

On Tuesday 24 June 2008, Clement Ow wrote:
> Hi everyone,
>
> I have 2 path names :
>
> C:/Ruby/20080205/2008
> C:/Ruby/2008
>
> I need a regular expression which can select just 2008 and utilise the
> string that contains just 2008 instead of 20080205.
>
> I tried using /2008/ but apparently it also picks up strings like
> 20080205.
> is there a way to rearrange the regexp such that only 2008 is selected?

If the part you're interested with is at the end of the string, you can use

/\d{4}\Z/

which matches four digits followed by the end of the string. Otherwise, you 
can use this:

/\d{4}(?:[^\d]|\Z)/

This will match four digits followed by either a non-digit character or by the 
end of the string.

I hope this helps

Stefano