From: Phlip <phlip2005@...>
Date: 2009-03-08T07:13:23+09:00
Subject: Re: how to un-ragged a 2D array?

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