From: Robert Klemme <shortcutter@...>
Date: 2010-03-09T22:25:34+09:00
Subject: Re: Flatten out Hash

2010/3/9 Glenn Ritz <glenn_ritz@yahoo.com>:
> Jean G. wrote:
>> On Tue, Mar 9, 2010 at 8:31 PM, Glenn Ritz <glenn_ritz@yahoo.com> wrote:
>>> Hi,
>>>
>>> I would like to take a nested hash that looks like this:
>>>
>>> {"a"=>{"b"=>{"c"=>1}, "b2"=>{"c2"=>2}}}
>>>
>>> and turn it into an array of 2 element arrays like this:
>>>
>>> [["a: b2: c2: ", 2], ["a: b: c: ", 1]]
>>>
>>
>> My method:
>>
>> hash = {"a"=>{"b"=>{"c"=>1}, "b2"=>{"c2"=>2}}}
>> array = []
>>
>> hash.keys.each do |k1|
>>     hash[k1].keys.each do |k2|
>>         hash[k1][k2].keys.each do |k3|
>>              array << ["#{k1}: #{k2}: #{k3}:",hash[k1][k2][k3]]
>>         end
>>     end
>> end
>
> Thanks, Jean.
>
> It's a good solution.  But it's dependent on there being 3 levels of
> hashes.  What if you didn't know how many levels of nesting there was
> before executing the code?  Suppose the hash looked like this instead:
>
> {"a"=>{"b"=>{"c"=>1}, "b2"=>{"c2"=> {"d2" => 2}}}}

Basically you want to do a DFS and store the path to the root for
every leaf.  Something like http://gist.github.com/326558

Kind regards

robert

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