From: Rick DeNatale <rick.denatale@...>
Date: 2007-05-13T01:20:59+09:00
Subject: Re: how to remove dups from 2 lists?

On 5/11/07, Wolfgang N�dasi-Donner <wonado@donnerweb.de> wrote:
> Wolfgang N�dasi-Donner schrieb:
> > Or is it something like this?
> >
> > ...
> > --- before ---
> > ["a", "b", "a", "a", "c", "a", "b", "c", "d", "e", "f", "e", "a"]
> > ["a", "b", "a", "c", "d", "c", "d", "c", "c", "g", "h", "g", "c"]
> > --- after ---
> > ["a", "a", "b", "e", "f", "e", "a"]
> > ["d", "c", "c", "g", "h", "g", "c"]
>
> If it is the wanted direction, the program is simple.
>
> class Array
>    def remdups(b)
>      a= self.dup
>      b.each{|el|a.delete_at(a.index(el)) if a.include?(el)}
>      a
>    end
> end

Or somewhat faster, particularly for long arrays:

class Array

  def rem_dups(b)
    a = dup
    b.each { | e | i = a.index(e); a.delete_at(i) if i}
    a
  end
end

Which avoids scanning the array twice for each element.


-- 
Rick DeNatale

My blog on Ruby
http://talklikeaduck.denhaven2.com/