From: "Ara.T.Howard" <ahoward@...>
Date: 2004-03-03T15:34:45+09:00
Subject: Re: why are Hashes so unsorted? what's your solution?

On Wed, 3 Mar 2004, Ruby Baby wrote:

> I try to avoid questions like "Why doesn't Ruby do what ___ does?"
> 
> But I'm stumped by hashes and asking for help to find a new solution.
> 
> I use MySQL databases a lot.  Let's say I have a query to find the
> top-selling albums in my store:
> 
> SELECT sku, artistname, albumtitle, sold FROM albums
> ORDER BY sold DESC LIMIT 20;
> 
> When I get the hash of results from the database, I'm used to making
> the "sku" the hash key since it's the only unique identifier.
> A perfect hash key.  Used everywhere by my iteration methods.
> 
> In PHP, this is no problem.  I get the hash, and I can do the 
> "each" iteration on it, and get my top-selling albums in order.
> 
> In Ruby, it's an unordered jumble.
> 
> Why is that?
> 
> And what do you think is the Ruby way solution for what I need to do?

http://raa.ruby-lang.org/list.rhtml?name=ruby-rbtree

it is ultra-fast and the keys come out in order:

~ > cat a.rb
#!/usr/bin/env ruby
require 'rbtree'
rb = RBTree.new
42.times{|i| rb[i] = i}
rb.each{|k,v| puts "#{ k } => #{ v }"}


~ > a.rb
0 => 0
1 => 1
2 => 2
3 => 3
<snip>
39 => 39
40 => 40
41 => 41



-a
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