From: Austin Ziegler <austin@...>
Date: 2004-03-18T13:37:18+09:00
Subject: Re: Slice or Value of Empty Array

On Thu, 26 Feb 2004 04:21:20 +0900, Jim Freeze wrote:
> On Thursday, 26 February 2004 at  3:56:57 +0900, Austin Ziegler wrote:
>> On Thu, 26 Feb 2004 03:34:03 +0900, Jim Freeze wrote:
>>> I am puzzling about the following:
>> (reformatted)

>> p [][0..0]    # => []
>> p [][0..-1]   # => []
>> p [][-1..-1]  # => nil

>>> If ary[n..n] returns a slice, then why does a[0..0] give me an empty
>>> array and a[-1..-1] give me nil?
>> Matz explained this some time ago. I think it has something to do with
>> indexes sitting *between* elements in Ruby arrays, and the last element
>> being precached as empty.
>>
>> I'm not sure if that makes any sense...
> Hmm, vaguely. Do you have the reference?

[ruby-talk:24773]

Sorry it took so long for me to get back to you on this. I'm not sure why it 
quite works the way that it does for [][-1..-1], but that explains the 
concept in general.

-austin
--
austin ziegler    * austin@halostatue.ca * Toronto, ON, Canada
software designer * pragmatic programmer * 2004.03.17
                                         * 23.33.28