From: jake kaiden <jakekaiden@...>
Date: 2011-10-19T04:58:36+09:00
Subject: Re: Local and Global Variable

hi Junayeed,

  check out this link for more info on ruby variables and constants...
http://en.wikibooks.org/wiki/Ruby_Programming/Syntax/Variables_and_Constants

  in general, global variables are a bad idea - and it's best to try and
stay away from them if you can.  you'll soon discover why yourself, as
you continue to use ruby more.  class, instance, and local variables
will usually cover all your needs.

  class variables exist and are the same across all instances and
methods of a given class.  instance variables exist and can be accessed
from all methods of an instance of a class, but are not shared by two
instances of the same class (changing one will not change the other.)
local variables exist only within the method or block in which they were
created.

  here's a quick comparison of instance variables and local variables:

#######
class VariableTester

  def initialize
    @instance = "I can travel between methods of this class"
    local = "I only exist in the `initialize` method"

    puts @instance
    puts local

    print_variables
  end

  def print_variables
    local = "I'm also called `local,` and I only exist in the
`print_variables` method"

    puts
    puts @instance
    puts local

    @instance = "I've been changed!"

    print_again
  end

  def print_again
    local = "I'm yet another local, and I can't leave the `print_again`
method."

    puts
    puts @instance
    puts local
  end

end

vt = VariableTester.new
#######


  hth,

  - j

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