From: Maarten Boonen <m44rt3n@...>
Date: 2004-12-16T07:12:15+09:00
Subject: Re: [ANN] rand.rb 0.9: Random access methods for Enumerables

Neil Spring schreef:
> On Dec 14, 2004, at 7:24 PM, Ilmari Heikkinen wrote:
> 
>> rand.rb is a library for picking random elements and shuffling.
>> This work is licensed under the same terms as Ruby itself.
> 
> 
> umm,  could you maybe replace:
> 
>   def shuffle!
>     sort!{rand <=> 0.5}
>   end
> 
> with:
> 
>   def shuffle!
>     each_index {|j| i = rand(size-j); self[j], self[j+i] = self[j+i], 
> self[j]}
>     self
>   end

I made this a function a few days ago and it seems to be a lot faster. 
Not sure if it's completely correct though.

def shuffle!
	a = 0
	while(a<length)
		b = (length*Kernel.rand).to_i
		tmp = self[a]
		self[a] = self[b]
		self[b] = tmp
		a+=1
	end
	self
end