From: Gennady Bystritsky <Gennady.Bystritsky@...>
Date: 2006-08-12T15:39:51+09:00
Subject: Re: Beginner's question: assigning same value to many variables

> -----Original Message-----
> From: Morton Goldberg [mailto:m_goldberg@ameritech.net] 
> Sent: Friday, August 11, 2006 9:21 PM
> To: ruby-talk ML
> Subject: Re: Beginner's question: assigning same value to 
> many variables
> 
> I presume you want each variable initialized to a _different_ empty  
> string. If so, I can't think of an easy way to do it using local  
> variables. That may just go to show my lack of ruby smarts. However,  
> it's not too hard to initialize a group of instance variables to  
> different empty strings in one line of code. Consider:
> 
> #! /usr/bin/ruby -w
> 
> class Foo
>     def initialize
>        %w[@a @b @c @d].each {|v| instance_variable_set(v, '')}
>     end
> end
> 
> foo = Foo.new
> p foo #=> #<Foo:0x2556c @c="", @b="", @a="", @d="">
> 
> And the following will work for global variables.
> 
> %w[$a, $b, $c, $d].each {|v| eval("%s=String.new" % v)}
> p [$a, $b, $c, $d] #=> ["", "", "", ""]
> 
> But for local variables, I don't know.

How about this:

irb(main):001:0> a, b, c = Array.new(3) { '' }
=> ["", "", ""]
irb(main):002:0> a
=> ""
irb(main):003:0> b
=> ""
irb(main):004:0> c
=> ""
irb(main):005:0> a.object_id
=> 203740
irb(main):006:0> b.object_id
=> 203730
irb(main):007:0> c.object_id
=> 203720
irb(main):008:0>

It will work for global and instance variables as well.

Best, 
Gennady.

> 
> Regards, Morton
> 
> On Aug 11, 2006, at 7:12 PM, Alex Khere wrote:
> 
> > I'm just starting out in programming, using Ruby to learn.
> >
> > I'm trying to write a short program that will use a handful of
> > variables, and I want to be sure that all of the variables 
> start with
> > the value '' (strings of zero length).
> >
> > Is there a way to list all of the variables on a single line and set
> > them to the same value? I tried using commas to seperate, but that
> > didn't work.
> >
> > I also tried creating an array with all of the variable 
> names and then
> > using "arrayname.each do |name|" to cycle through the 
> assignment, but
> > since the varibles hadn't been defined, I got an "undefined local
> > variable or method" error (at least, I think that's why I got an  
> > error).
> 
> 
>