From: "Jesús Gabriel y Galán" <jgabrielygalan@...>
Date: 2012-07-02T16:52:53+09:00
Subject: Re: how to sort this nested hash

On Mon, Jul 2, 2012 at 9:21 AM, yibin z. <lists@ruby-forum.com> wrote:
> s = {'s1'=>{'hn1'=>{'15'=> {'m1'=> ['aa', 'bb'] }}}, 's3'=>{'hn2'=>{'10'
> => {'m2' => ['cc'] }}}, 's2'=>{'hn3'=>{'50'=> {'m3' => ['dd'] }}}}
>
> How to sort the above nested hash by keys like '15', '10', '50' shown
> above?
>
> The result should look like:
>
> {'s2'=>{'hn3'=>{'50'=> {'m3' => ['dd']}}}, 's1'=>{'hn1'=>{'15'=> {'m1'=>
> ['aa', 'bb'] }}}, 's3'=>{'hn2'=>{'10' => {'m2' => ['cc'] }}}}

First of all, a Hash is not sorted, so the result cannot be what you
typed. You can sort a Hash and store the result in somethins that is
sorted, like an array. Next, you can use the method sort_by, which
sorts an Enumerable object by the computation of the block you pass to
it. Your structure is a bit complex, too much nesting there, but
something like this could work:

1.9.2p290 :007 > s.sort_by{|k,v| tmp = v[v.keys.first];  -
(tmp.keys.first).to_i}
 => [["s2", {"hn3"=>{"50"=>{"m3"=>["dd"]}}}], ["s1",
{"hn1"=>{"15"=>{"m1"=>["aa", "bb"]}}}], ["s3",
{"hn2"=>{"10"=>{"m2"=>["cc"]}}}]]

Jesus.