From: yermej <yermej@...>
Date: 2008-01-24T23:59:58+09:00
Subject: Re: Change a data structure

On Jan 24, 2:14 am, Michael Schmarck <michael.schma...@here.la> wrote:
> Hello!
>
> I've got the following data structure, which I need to change, to
> suit further needs:
>
> timing_given = {
>   "Performance Test of Item Access using Lists" => [
>     {"Plants" => 100, "Customers" => 50, "Total" => 150},
>     {"Plants" => 85,  "Customers" => 60, "Total" => 140},
>     {"Plants" => 111, "Customers" => 77, "Total" => 188}
>   ],
>   "Performance Test of Item Access using Advance Item Search" => [
>     {"Work List" => 17, "Total" => 42},
>     {"Work List" => 10, "Total" => 50},
>     {"Work List" => 22, "Total" => 99},
>     {"Work List" => 15, "Total" => 60}
>   ]
>
> }
>
> Now I'd like to change that, so that it looks somewhat like this:
>
> timing_wanted = {
>  "Performance Test of Item Access using Lists" => {
>    "Plants" => [100, 85, 111], "Customers" => [50, 60, 77], "Total" => [150, 140, 188]
>  },
>  Performance Test of Item Access using Advance Item Search" => {
>    "Work List" => [17, 10, 22], "Bookmarks" => [30, 33, 27], "Total" => [42, 50, 99]
>  }
>
> }
>
> Let me explain...
>
> I've got a hash called "timing_given", which has, right now, two keys.
> These keys have arrays as values. The elements of these arrays are again
> hashes.
>
> Now this should be changed to match what's shown in "timing_wanted". Ie.,
> create a hash, which has two keys. These keys should have hashes as values
> and the values of these hashes should be arrays.
>
> The data represent some timing measurement data. In the example I'm showing,
> the Plants, Customers and Total tests have been run 3 times, consecutively.
> So, first the Plants test was run, then the Customers test and then the
> Total test.
>
> I want to collect all the Plants (etc.pp.) tests in one array. This array
> should have as many elements, as there were test runs for the Plants test.
> Accordingly for the other tests.
>
> In reality, there are more tests than what I've shown. And as you can see,
> there are two test "categories", called "Performance Test of Item Access
> using Lists" and "Performance Test of Item Access using Advance Item Search".
> In reality, there might be more. Under these categories, there might be
> 2, 3, 4 or whatever test runs - but the number of test runs for a category
> is always constant.
>
> How would I best "mess up" that timing_given data structure, so that it
> resembles the timing_wanted structure?
>
> Thanks a lot,
> Michael

I'll offer up an inject version (mostly for novelty's sake):
timing_given.each {|k, v| timing_given[k] = v.inject(Hash.new {|h, k|
h[k] = []}) {|acc, h| h.each {|k, v| acc[k] << v}; acc}}