From: Robert Klemme <shortcutter@...>
Date: 2011-07-24T01:03:08+09:00
Subject: Re: regex oddity

On Fri, Jul 22, 2011 at 8:41 PM, Roger Pack <rogerpack2005@gmail.com> wrote:
> Anybody know why this occurs?
>
>>> 'a'.scan /.*/
> => ["a", ""]
>
> Is this normal/expected?

Yes.  Scanning will start at pos 0 of the string and match as long as
it can (i.e. until the end of the string): you get "a".  Next,
position is increase (now 1, *at* the end) and since .* matches the
empty string alas we have a match here as well: "".  Next position is
*after* the end => no more matches.

If you want to see regexp engine matching in action you can use regexp
coach which is a nice tool to explore such things (albeit not with
ruby's regexp engine).

Kind regards

robert

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