From: Florian Gilcher <flo@...>
Date: 2011-07-16T22:30:46+09:00
Subject: Re: does OrderedHash exist?


On Jul 16, 2011, at 2:32 PM, Robert Klemme wrote:

> On Sat, Jul 16, 2011 at 9:34 AM, Oren Shani <orenshani7@gmail.com> wrote:
>> I created a class called, HashArray which implements a pretty
>> straightforward Hash with order object. Content can be added, deleted,
>> reordered, etc, and then there is the as_array method that enables using
>> the object as an array.
> 
> I'm curious how you manage to keep the data structure ordered and keep
> access time O(1).  It surely is O(1) since it's called _Hash_Array,
> isn't it?
> 
> Kind regards
> 
> robert

Not speaking for the OP, but the naive solution by keeping book of key
ordering in an Array for ordered access (mostly iteration) and going
straight for a plain Hash for storage and unordered access already 
fulfills that. Non-trivial insertion would suffer, because it has to 
reorganize the keys.

Regards,
Florian