From: Martin DeMello <martindemello@...>
Date: 2008-08-08T02:40:28+09:00
Subject: [ruby-core:18172] Re: New array methods cycle, choice, shuffle (plus bug in cycle)

On Thu, Aug 7, 2008 at 3:11 AM, Yukihiro Matsumoto <matz@ruby-lang.org> wrote:
> Hi,
>
> In message "Re: [ruby-core:18164] Re: New array methods cycle, choice, shuffle (plus bug in cycle)"
>    on Thu, 7 Aug 2008 18:35:28 +0900, gdefty@attglobal.net writes:
>
> |I have the same expectation of the order being
> |preserved. It is not because I have any particular
> |reason to preserve it, but simply because that is
> |how I would expect a reasonable implementation to
> |work.
>
> I am against #sample! for the name.  If one try to persuade me to add
> a method with the behavior, the name should be anything but #sample!

The name seems good to me - it ties in with the statistical usage of
sample-with-replacement and sample-without-replacement. Maybe #pick!
instead. It seems analogous to having #slice and #slice!

> I believe the calculation complexity of shuffle-once-and-pop is far
> lesser than pick-some-elements-and-remove-them, even with an array of
> thousands of elements.

As a first step, we could have #delete_at accept multiple arguments,
and optimise it in C to delete multiple elements efficiently. Does
#sample already take not selecting the same element twice into
account?

martin