From: Philip Mak <pmak@...>
Date: 2002-08-27T07:14:19+09:00
Subject: Hybrid hash and array?

When programming radio buttons on a website, I find myself using this
sort of construct a lot:

    @choices = [
        ['1', 'Spring'],
        ['2', 'Summer'],
        ['3', 'Fall']
    ]

    @table = {}
    @choices.each do |key, value|
        @table[key] = value
    end

The data structure I really want is like a hash, except that it
maintains its key/value pairs in the order that I defined them.

Or, looking at it another way, I want an array of arrays, except that
it can be accessed using the key (where the key is the first element
of each array inside the outer array).

Currently, I define it as an array of arrays, and then have a bit of
code to convert it into a hash. Then when I need it in order, I use
the array, and when I need to lookup by key, I use the hash.

Is there a built-in class that Ruby has which would automate this?