From: Michael Schmarck <michael.schmarck@...>
Date: 2008-01-25T00:04:56+09:00
Subject: Changing an array data structure

Hello.

I already asked about how I'd best re-order a datastructure. But 
thinking about, I changed my mind; instead of the hash approach
I've shown in <news:6233013.YDsyxgeUJ1@michael-schmarck.my-fqdn.de>,
I now think I might use arrays instead. Reason: The order in which
something is inserted and later fetched is important to me. With
Hashes in 1.8, this cannot easily be done out-of-the-box, can it?

Anyway - I'm now looking for a way to change the following arry:

timing = [
      ["Performance Test of Item Access using Lists", [
          [["Plants", 100], ["Customers", 50], ["Total", 150]],
          [["Plants",  85], ["Customers", 60], ["Total", 145]],
          [["Plants", 111], ["Customers", 77], ["Total", 188]]
      ]],
      ["Performance Test of Item Access using Advance Item Search", [
          [["Work List", 17], ["Bookmarks", 30], ["Total", 42]],
          [["Work List", 10], ["Bookmarks", 33], ["Total", 50]],
          [["Work List", 22], ["Bookmarks", 27], ["Total", 99]]
      ]]
]
# This should become:
timing_reordered = [
     ["Performance Test of Item Access using Lists", [
         ["Plants", [100, 85, 111]], ["Customers", [50, 60, 77]], ["Total", [150, 145, 188]]
     ]],
     ["Performance Test of Item Access using Advance Item Search", [
         ["Work List", [17, 10, 22]], ["Bookmarks", [30, 33, 27]], ["Total", [42, 50, 99]]
     ]]
]

It very much resembles the datastructure shown in the hash approach.
That's only natural, if you take into consideration how the data is
generated. To do that, I'm running a method 3 (or more) times; these
methods generate the "Performance Test of Item Access using Lists"
and "Performance Test of Item Access using Advance Item Search" data.
These methods generate data; data items for Plants, Customers and
so on.

But for reporting, it's best for me, if all the eg. Plants results
are "grouped together". Actually, I only need the innermost arrays,
ie. [100, 85, 111], [50, 60, 77], .... These arrays should be 
concated, so that I've only got one long array, starting with: [100,
85, 111, 50, 60, 77, ...].

Well - how would I reorder the array best? I tried:

        timing.each { |test|
          ...
        }

But actually, I already fail to go on there. Now "test" is an array.
When I access test[0], I get the "category labels" ("Performance 
Test of ....") and with test[1], I get the entries. Ie.:

        Plants
        100
        Customers
        50
        Total
        150

If I add another "each loop" into that existing loop, I don't get
what I'd expect. I tried:

        timing.each { |test|
          test[1].each { |test_values|
            puts test_values[0]
          }
        }

Now I'd expect to get Plants, Customers, Total, Work Lists, Bookmarks,
Total. But I get:

        Plants
        100
        Plants
        85
        Plants
        111
        Work List
        17
        Work List
        10
        Work List
        22

So I only get the 1st "column" of the input data. Why's that? And
how would I do that correctly, as that's obviously not the right
way to go?

Thanks again,
Michael