From: Michael Fellinger <m.fellinger@...>
Date: 2009-03-08T09:22:47+09:00
Subject: Re: how to un-ragged a 2D array?

On Sun, Mar 8, 2009 at 7:13 AM, Phlip <phlip2005@gmail.com> wrote:
> Ktx! Now, on to Round Two!
>
> What if the array were even _more_ ragged??
>
>   [   1     ,
>     [ 2, 3 ],
>       4     ,
>     [ 5, 6 ],
>       7     ,
>       8      ]
>
> The back-story here is: We are asking the user-programmer to enter either
> items or couplets of items. Consider the ActiveRecord DSL, where an :include
> => item, for example, can be a single item, or an array of items, or a hash
> of paired items, or a hash pointing to an array of items, and so on. AR
> _could_ interpret :include => item by promoting all its scalars to arrays,
> then running a simpler algorithm that only expects arrays.
>
> In my case, the user-programmer can leave the second 1, 4, 7, & 8 out, as a
> convenience, but the algorithm wants this...
>
>   [ [ 1, 1 ],
>     [ 2, 3 ],
>     [ 4, 4 ],
>     [ 5, 6 ],
>     [ 7, 7 ],
>     [ 8, 8 ] ]
>
> ...as an internal convenience.
>
> My attempt is needs = needs.map{|x| x.is_a?(Array) ? x : [x,x] }, which is
> truly icky, but might be the shortest way. Besides this!
>
>      needs = needs.map{|x| [x,x].flatten[0..1] }
>
> --
>  Phlip
>
>

needs.map{|e| ([*e] * 2).first(2) }

^ manveru