From: Zhao Yi <youhaodeyi@...>
Date: 2008-12-18T09:55:32+09:00
Subject: Re: A question about ruby array

David A. Black wrote:
> It's actually hashes, not arrays, that use this syntax (see other
> reply in this thread). What the :id thing means is that :id is a
> Symbol object. Symbol is a class of objects that correspond directly
> to entries in Ruby's internal symbol table. There's one entry for
> every identifier in use while your program is running: every variable
> name, method name, and constant. If you want to see them all, you can
> do:
> 
>    Symbol.all_symbols
> 
> in irb.
> 
> The symbol table is really part of the inner workings of the
> interpreter, but Ruby exposes it to programmer-space through the
> Symbol class. Symbols have characters; therefore, they're used a lot
> in situations where you might also use strings (such as hash keys).
> They're more lightweight in terms of processing than strings are: a
> string has to know how to resize itself, for example, whereas a symbol
> is immutable.
> 
> 
> David

Ok I understand,

thanks for your explanation.
-- 
Posted via http://www.ruby-forum.com/.