From: Pit Capitain <pit@...>
Date: 2007-03-28T22:23:58+09:00
Subject: Re: String Intersection. A better way

Daniel N schrieb:
> I have an issue with strings.  I want the intesection of two strings but 
> I'm
> not sure how to go about it.  I have two cases.
> (...)

Daniel, if your strings aren't too big, you could try this:

   class String
     def intersection_at_start(other)
       not empty? and other[/#{split(//)*"("}#{")?"*(size-1)}\z/]
     end
     def intersection_at_end(other)
       other.intersection_at_start(self)
     end
     def &(other)
       intersection_at_start(other) or intersection_at_end(other) or ""
     end
   end

I don't know if this is faster than your original implementation, and it 
certainly isn't easier to understand, but at least it passes Rob's tests.

Regards,
Pit