From: "Jesús Gabriel y Galán" <jgabrielygalan@...>
Date: 2009-01-13T06:01:16+09:00
Subject: Re: what's the rules re whether a Hash can use either a Symbol or String to reference the value???

On Mon, Jan 12, 2009 at 9:50 PM, Greg Hauptmann
<greg.hauptmann.ruby@gmail.com> wrote:
> Hi,
> Getting confused with Hashes a bit.  It seems sometimes I can use both a
> Symbol or a String to get the value back, but other times the Symbol doesn't
> work.  Is there any rule re how to remember how Hash handles setting and
> getting values uses Symbol / String?
>
> e.g. hash_variable[:amount] versus hash_variable["amount"]
>
> e.g. hash_var = {:amount => 10}, versus hash_var = {"amount" => 10)

In general, a hash uses eql? to know if a key matches the one you are
asking for.
So in general a Symbol and it's String counterpart are not the same
key in a hash.
There are different implementations that allow using Strings / Symbols
to refer to the same key.
Search for HashWithIndifferentAccess or something like that. I think
Rails uses something similar, IIRC.
Maybe your confusing comes from the different behaviour when you are
using Rails vs non-Rails?

Jesus.