From: Phrogz <gavin@...>
Date: 2007-02-09T08:05:06+09:00
Subject: Re: Ruby hash equlity

Finally, here's a slightly better version. It's still O(n^2) in the
worst case, but should perform much better under common circumstances
(in case someone actually needed this functionality):

class Hash
  # Ouch! O(n^2) performance
  # Bad for hashes with many keys
  def sort_of_equal( other )
    equal = true
    self.each{ |k,v|
      unless found_key = (other[k]==v)
        other.each{ |k2,v2|
          break if found_key = ( ( k==k2 )  && ( v==v2 ) )
        }
      end
      equal &&= found_key
    }
    equal
  end
end

Note that this will still not work if you have nested hashes that you
want to treat like this. You'd need to override Hash#== fully, or put
in tests based on key and value type.