From: sto.mar@...
Date: 2012-11-30T15:22:32+09:00
Subject: Re: Ordered Hash (v. 1.8)

Am 30.11.2012 07:15, schrieb sto.mar@web.de:
> Am 30.11.2012 02:46, schrieb Doug Jolley:
>> I am running Ruby v. 1.8.7 and I have installed the orderedhash gem.  I
>> know that the purpose of orderedhash is to preserve the order of
>> creation.  However, what I'd really like to do is, after the hash has
>> been created, sort it on the key in a manner similar to the way that I
>> would sort an array with the sort!() method and then preserve the sorted
>> order.  Any ideas on how I might accomplish that feat?  Thanks for any
>> input.
>>
>>       ... doug
>
> 1. You could use the RBTree gem.
>
> 2. Iterate through the sorted keys when you need to access elements
>     in sorted order:
>
> 1.9.3p194 :001 > hash = {:c => 1, :a => 2, :b => 3}
>   => {:c=>1, :a=>2, :b=>3}
> 1.9.3p194 :002 > sorted_keys = hash.keys.sort
>   => [:a, :b, :c]
> 1.9.3p194 :003 > sorted_keys.each do |key|
> 1.9.3p194 :004 >     puts "#{key} => #{hash[key]}"
> 1.9.3p194 :005?>   end
> a => 2
> b => 3
> c => 1
>   => [:a, :b, :c]

correction: in 1.8, when your keys are symbols you need to sort with

   sorted_keys = hash.keys.sort_by(&:to_s)

-- 
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