Re: Beginner's question: assigning same value to many variables

-----Original Message-----
From: Morton Goldberg [mailto:m_goldberg@xxxxxxxxxxxxx]
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).




.

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