From: Lars Haugseth <ruby-talk@...>
Date: 2012-06-27T00:01:05+09:00
Subject: Re: Array#sample is Set#sample and not Array#sample !

On 06/26/2012 04:50 PM, Josh Cheek wrote:
> On Tue, Jun 26, 2012 at 4:48 AM, Lars Haugseth
> <ruby-talk@larshaugseth.com <mailto:ruby-talk@larshaugseth.com>> wrote:
>
>     I agree, sample isn't intended to work the way the OP suggests.
>
>     There are other ways to achieve the desired effect:
>
>       class Array
>         def ordered_sample(n)
>           values_at [*0...size].sample(n).sort
>         end
>       end
>
>       a = [:a, :b, :c, :d, :e, :f, :g, :h]
>
>       a.ordered_sample(4)
>       => [:b, :c, :d, :e]
>       a.ordered_sample(4)
>       => [:c, :d, :e, :h]
>       a.ordered_sample(4)
>       => [:a, :b, :c, :g]
>
> Maybe we're on different rubies, but I had to change the implementation
> to `values_at *[*0...size].sample(n).sort`

You're right, I did a copy&paste error and forgot to test my latest edit 
to the email.

A bit more readable:

  values_at size.times.to_a.sample(n).sort

-- 
Lars Haugseth