From: Adam Prescott <adam@...>
Date: 2011-06-21T23:46:09+09:00
Subject: Re: How to order a hash based on its keys?

On Tue, Jun 21, 2011 at 3:34 PM, Iñaki Baz Castillo <ibc@aliax.net> wrote:
> Hi, I want to order a hash using itds keys:
>

When you hear "order" and "hash" in the same sentence, you should
think "hashes aren't ordered".

>  irb> a = { 2=>"2", 3=>"3", 1=>"1" }
>  irb> a.sort
>  [[1, "1"], [2, "2"], [3, "3"]]
>
> But I want a resulting hash with keys ordered:
>
>  { 1=>"1", 2=>"2", 3=>"3"}
>
> Is there any efficiente way? (I don't want the hast to be converted to
> an array and the to a hash again).
>

1.9 keeps hashes initially in insertion order, but if you don't create
your hash with the keys in the order you want, since Hash isn't
ordered, I don't think there's a way to get what you want without
creating an Array and then a second Hash, with the keys in the order
you want.