From: Arun Kumar <arunnandu@...>
Date: 2008-05-02T21:16:03+09:00
Subject: Re: Beginner Question on Ruby

------=_Part_8995_30642321.1209730560857
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Content-Disposition: inline

Hello David,

Thanks for the answer.

But would you know why it is so? Is there something syntactic or semantic
issue that I am making,

the reason i ask this is...

n = 10
x += n
does a perfect x = nil + n => n initialization, which is good and
explainable.

In the array case however,
One would expect [atleast i am :) ] the elements of the source array [if
any] be appended to the target. Now why is the reference going in making it
a recursive :?

sorry if this question is lame or bozo but i feel a clear behaviour enables
clear understanding or would require even more clearer reasoning.

Cheers
Arun

On Fri, May 2, 2008 at 5:27 PM, David A. Black <dblack@rubypal.com> wrote:

> Hi --
>
>
> On Fri, 2 May 2008, Arun Kumar wrote:
>
> Hi all,
> >
> > I am beginning to learn ruby and cant seem to reason this behaviour. I
> > expect since empty or nill is the array, arr*n shouldnt change it.
> >
> > Why is this behaviour so?
> >
> > Code:
> >
> > num_arr = Array.new
> > puts "Num Alpha: #{num_arr} and size: #{num_arr.size}"
> > puts "Num Alpha: #{num_arr << num_arr} and size: #{num_arr.size}"
> > num_arr.insert(-1, num_arr << num_arr)
> > puts "Num Alpha: #{num_arr} and size: #{num_arr.size}"
> >
> > Output:
> >
> > Num Alpha:  and size: 0
> > Num Alpha: [...] and size: 1
> > Num Alpha: [...][...][...][...][...][...][...][...][...] and size: 3
> >
>
> You're inserting an array into itself. Ruby represents that kind of
> recursive inclusion with dots.
>
> irb(main):005:0> a = []
> => []
> irb(main):006:0> a << a
> => [[...]]
>
>
> David
>
> --
> Rails training from David A. Black and Ruby Power and Light:
>  INTRO TO RAILS         June 9-12            Berlin
>  ADVANCING WITH RAILS   June 16-19           Berlin
>  INTRO TO RAILS         June 24-27           London (Skills Matter)
> See http://www.rubypal.com for details and updates!
>
>

------=_Part_8995_30642321.1209730560857--