[#376274] Best Linux Distro for Ruby? — Nick Hird <boondox@...>

What are some of the better linux distro's for ruby development? I know

15 messages 2011/01/02

[#376329] Is singleton class of an object already created? — Samnang Chhun <samnang.chhun@...>

I would like to know is there any ways to check is singleton class of an

12 messages 2011/01/04

[#376333] Threading in ruby — "Vishnu I." <pathsny@...>

Hi

13 messages 2011/01/04
[#376335] Re: Threading in ruby — Robert Klemme <shortcutter@...> 2011/01/04

On Tue, Jan 4, 2011 at 8:41 AM, Vishnu I. <pathsny@gmail.com> wrote:

[#376339] ripl - an irb alternative - 0.3.0 released — ghorner <gabriel.horner@...>

ripl, a light modular alternative to irb, has reached 0.3.0. ripl

32 messages 2011/01/04

[#376382] Class Initialization? — Kedar Mhaswade <kedar.mhaswade@...>

I have a class and two class methods: self.encode and self.decode. The

14 messages 2011/01/05
[#376385] Re: Class Initialization? — Andrew Wagner <wagner.andrew@...> 2011/01/05

On Wed, Jan 5, 2011 at 9:33 AM, Kedar Mhaswade <kedar.mhaswade@gmail.com>wrote:

[#376388] Petition to add Metasploit Project as Ruby success story — Christian Kirsch <Christian_Kirsch@...7.com>

I noticed the Ruby success stories on the Ruby website. I would like to make a petition to list the open source Metasploit Project as a success story for the Ruby website. The Metasploit Project has seen more than a million unique downloads in the past 12 months and has over 700,000 lines of code, compared to 100,000 lines of the highly successful Ruby projects Puppet and Ruby on Rails.

10 messages 2011/01/05

[#376453] Block variable - How is it read in English? — SW Engineer <abder.rahman.ali@...>

Following the "Ruby on Rails Tutorial", and under section "6.1.1

16 messages 2011/01/06

[#376574] Best way for Array#find+transform ? — "Jonas Pfenniger (zimbatm)" <jonas@...>

There is a pattern that I'm using quite regularly, but I'm not

17 messages 2011/01/08
[#376575] Re: Best way for Array#find+transform ? — Anurag Priyam <anurag08priyam@...> 2011/01/08

> I know I can come up with a new method on Array that would shorten this to:

[#376576] Re: Best way for Array#find+transform ? — Anurag Priyam <anurag08priyam@...> 2011/01/08

> paths.map{|path| File.join(path, filename)}.select{|name| File.exist?(path)}

[#376577] Re: Best way for Array#find+transform ? — "Jonas Pfenniger (zimbatm)" <jonas@...> 2011/01/09

2011/1/8 Anurag Priyam <anurag08priyam@gmail.com>:

[#376579] Re: Best way for Array#find+transform ? — David J. Hamilton <groups@...> 2011/01/09

Excerpts from Jonas Pfenniger (zimbatm)'s message of Sat Jan 08 16:05:05 -0800 2011:

[#376586] Re: Best way for Array#find+transform ? — "Jonas Pfenniger (zimbatm)" <jonas@...> 2011/01/09

2011/1/9 David J. Hamilton <groups@hjdivad.com>:

[#376606] Re: Best way for Array#find+transform ? — David J. Hamilton <groups@...> 2011/01/10

Excerpts from Jonas Pfenniger (zimbatm)'s message of Sun Jan 09 04:08:10 -0800 2011:

[#376680] Parallel Assignments and Elegance/Complexity Ratio. — Kedar Mhaswade <kedar.mhaswade@...>

In SICP, I read that "Programs should be written for people to read, and

15 messages 2011/01/11
[#376697] Re: Parallel Assignments and Elegance/Complexity Ratio. — Josh Cheek <josh.cheek@...> 2011/01/11

On Tue, Jan 11, 2011 at 8:29 AM, Kedar Mhaswade <kedar.mhaswade@gmail.com>wrote:

[#376682] JRuby 1.6.0.RC1 released — Thomas E Enebo <tom.enebo@...>

The JRuby community is pleased to announce the release of JRuby 1.6.0.RC1.

14 messages 2011/01/11

[#376744] Case statements - Just beautification — flebber <flebber.crue@...>

I just want to clarify case statements the name after the word case is

10 messages 2011/01/12

[#376792] Ruby is interpreted and scripting language? — Sai Babu <sateesh.mca09@...>

I am ruby fresher.

16 messages 2011/01/13

[#376855] Retrieving and copying element from array — Simon Harrison <simon@...>

If I have an array like this:

11 messages 2011/01/13

[#376898] What are your ruby rough cuts ? — "Jonas Pfenniger (zimbatm)" <jonas@...>

Hi rubyists,

32 messages 2011/01/14
[#376930] Re: [poll] What are your ruby rough cuts ? — David Masover <ninja@...> 2011/01/15

On Friday, January 14, 2011 07:34:04 am Jonas Pfenniger (zimbatm) wrote:

[#376937] Re: What are your ruby rough cuts ? — Joseph Lenton <jl235@...> 2011/01/15

David Masover wrote in post #975080:

[#376959] Why Quby? (was Re: What are your ruby rough cuts ?) — David Masover <ninja@...> 2011/01/15

On Saturday, January 15, 2011 04:42:58 am Joseph Lenton wrote:

[#377020] Obscure syntax error — Rolf Timmermans <molfie@...>

Hi all,

16 messages 2011/01/17

[#377052] Calling by Reference - Two Questions — Mike Stephens <rubfor@...>

I know I'm not the first person to get stumped by how to get Ruby to

15 messages 2011/01/18

[#377072] The most recommended way of naming methods in Ruby — Edmond Kachale <edmond.kachale@...>

Rubists,

14 messages 2011/01/18
[#377082] Re: The most recommended way of naming methods in Ruby — Phillip Gawlowski <cmdjackryan@...> 2011/01/18

On Tue, Jan 18, 2011 at 9:16 AM, Edmond Kachale

[#377121] Improving performance of hash math — dblock <dblockdotorg@...>

I am trying to improve performance of Euclidian distance between two

13 messages 2011/01/19

[#377226] Totally lost in learning Ruby — Hilary Bailey <my77elephants@...>

This is my second attempt to understand Ruby. I completely read 1)

61 messages 2011/01/21
[#378239] Re: Totally lost in learning Ruby — Hilary Bailey <my77elephants@...> 2011/02/08

Hi everybody,

[#378246] Re: Totally lost in learning Ruby — Robert Klemme <shortcutter@...> 2011/02/08

On Tue, Feb 8, 2011 at 3:16 AM, Hilary Bailey <my77elephants@gmail.com> wrote:

[#377236] using gems installed via 'sudo gem install' — "Piotr S." <thisredoned@...>

I've installed ruby-opengl through sudo gem install because there were

15 messages 2011/01/21

[#377362] pg gem 0.10.1 wth Ruby 1.9.2 does not work with method @pg_conn.exec_prepared(stmt_name, parameters) — Zeno Davatz <zdavatz@...>

Hi

9 messages 2011/01/24

[#377388] The finer points of postfix conditionals. — Jon Leighton <j@...>

Hi,

13 messages 2011/01/24

[#377411] Obtain data from .csv — Kamarulnizam Rahim <niezam54@...>

Sample of .csv file:

19 messages 2011/01/25

[#377609] why is overloading invalid in ruby. — Ted Flethuseo <flethuseo@...>

I don't understand why when I try to overload I get an error. Can I

36 messages 2011/01/27

[#377645] If you had the choice between Ruby & Groovy — Noah Cutler <sit1way@...>

Hey All.

15 messages 2011/01/28

[#377650] IDE? — <johan.tempelman@...>

Hi,

13 messages 2011/01/28

[#377703] Zlib::GzipReader and multiple compressed blobs in a single stream — Jos Backus <jos@...>

Hi,

11 messages 2011/01/28

[#377761] New to programming AND new to Ruby — "Cassandra K." <cassandra.k@...>

Hello. I am trying to teach myself Ruby. I have no background in

13 messages 2011/01/31

[#377785] 2011: Which Ruby books have you read? And which would you recommend? — "Aston J." <azzzz@...>

I know there are a lot of threads about books, but some of them are as

16 messages 2011/01/31

[#377800] How to know the exit status within at_exit() block? — Iñaki Baz Castillo <ibc@...>

Hi, my program invokes "exit true" or "exit false" and I want to catch

17 messages 2011/01/31

Re: Easiest way in Ruby to express "given this, set target to this if nil or undefined, else increment by this"

From: Jeremy Bopp <jeremy@...>
Date: 2011-01-23 05:26:24 UTC
List: ruby-talk #377296
On 01/22/2011 10:50 PM, RichardOnRails wrote:
> The following works,  but I'd prefer not to have to class values:
> 
> class Z
>     def self.show_z
> 	@@zz ||= 0; @@zz += 1
> 	puts @@zz
>     end
> end
> Z.show_z	# => 1
> Z.show_z	# => 2

Replace the @@'s with @'a so that you use a class instance variable
instead.  In this case it works effectively the same while avoiding the
nasty class variables.

> I tried this:
> 
> $h = Hash.new(:y)
> def show_y
>     $h[:y] ||= 0; $h[:y] += 1 # => Error msg # Line 18
>     puts $h[:y]
> end
> show_y
> show_y
> 
> but it doesn't pass muster with Ruby 1.8.6.  I get a complaint about
> the first line in show_y, which makes no sense IMHO:
> 
> TestOrEqual_operator.rb:18:in `show_y': undefined method `+'
> for :y:Symbol (NoMethodError)
> 	from TestOrEqual_operator.rb:21

The error is ultimately the result of the way you initialized your Hash
instance.  By passing :y to the new method, you arranged for any
uninitialized key referenced within the hash to have the symbol :y as a
value.  Therefore,

$h[:y] ||= 0

doesn't do anything because $h[:y] has a value of :y by default.  The
next statement then attempts to increment the value of $h[:y] by 1 and
fails because that value is :y and the + method is not defined for
Symbols.  If what I'm saying isn't exactly clear, try this:

h = Hash.new(:howdy)
puts h['Say hello like a Texan!']
puts h['Now say hello like a John Wayne!']

You could avoid this particular problem by simply setting $h to {}
rather than calling Hash.new(:y).  But why is a hash necessary for this
at all???  You could just as easily do this:

def show_y
  $y ||= 0
  $y += 1
  puts $y
end

This still leaves you using a global, but it's much simpler.  More
importantly, it works. ;-)

> Also, I'd be able to use a succinct version of this without resorting
> to globals.

Without knowing more about the problem you're trying to solve, it's hard
to provide a better response.  Apparently, you want to call a method
that automatically initializes some state when needed and then modify
and preserve that state between subsequent calls to that method.  That
state, be it a number as in your examples here or something else, has to
be stored somewhere.

I'm not a fan of globals in general, so I would choose to keep the state
in a class as you did in your first example.

-Jeremy

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