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Ruby: Most Popular Articles

These articles are the most popular over the last month.
How to Create Arrays in Ruby
This article explains and teaches how to use a arrays as a way to store multiple variables in one data structure.
How to Fix Missing Class or Module Errors
Problem: You encounter an error reading NameError: uninitialized constant Something or NameError: uninitialized constant Object::Something (with various class names in place of Something).
A Quick Guide to Creating and Using Hashes in...
This article explains and teaches how to use a associative arrays (hashes) as a way to store multiple variables in one data structure.
Getting Gaming With Rubygame
Loading images from files and displaying them om the screen is the one of the most basic things you can do in game programming. Luckily, Rubygame makes this really simple.
The Main Loop
The main loop is the heartbeat of any game, and is the first thing you need to learn to start making your own games.
What Every Coder Should Know About Running Ruby...
Learn how to use the command line interface on Windows, Linux and OS X to run rb files and use the interactive Ruby program. Page 2.
A Quick Guide to Forming Command Line Arguments...
Use command-line arguments to pass parameters to your Ruby scripts from the command line.
A Quick Guide to Using Environmental Variables...
Using environment variables in Ruby.
How to Use 'Loops' in Ruby (While, Until, Each,...
Loops, including while and include loops, are one of the most commonly used constructs in computer programs. Page 2.
Using the 'split' Method in Ruby
String manipulation using the split method in Ruby. Split strings into a list of substrings.
How to Use Comments for Ruby Code
Use comments to annotate your Ruby code.
How to Use 'Ternary' (Conditional) Operators in...
class="no-js" itemscope itemtype="http://schema.org/Article" > itemprop="description" >The ternary (or
How to Use Case (Switch) Statements in Ruby
The case statement is a control structure that is usually quite limited in other programming langauges. However, it's quite powerful and flexible in Ruby.
How to Use OptionParser: Ruby's Powerful...
Ruby comes equipped with a powerful and flexible tool to parse command-line options, OptionParser. The class is an alternative to GetoptLong for analyzing command line options.
Splitting Strings
Unless user input is a single word or number, that input will need to be split, or turned into a list of strings or numbers.
Here's What Ruby Is
What type of language is the Ruby programming language?
Creating a URL Shortener in Rails
The following is a list of articles that will show you how to write, style and deploy a URL shortener (like TinyURL) application in Ruby on Rails.
How to Create a URL Shortener in Ruby on Rails...
URL shortening is a useful feature for any Rails application. Making it easy for people to share links to your content is always a good thing.
A Quick Guide to Installing Ruby on Linux
How to install Ruby on the Linux operating system.
A Simple Guide to Using the Command Line in Ruby
How to use the command line interface on Windows, Linux and OS X to run Ruby scripts and use the interactive Ruby program.
Using Strings
Using and manipulating strings and substrings in Ruby. Page 4.
NameError: undefined local variable or method...
Problem: You encounter an error reading NameError: undefined local variable or method `a' for # or NameError: undefined local variable or method `a' for main:Object (with various identifiers in place of 'a').
Ruby on Rails 3 Tutorial Live Lessons
The Ruby on Rails 3 Tutorial by Michael Hartl is the antithesis of the rapid screencast approach. In the tutorial, the reader is walked through how to use Rails slowly and now with the live lesson video instructions Hartl has applied this philosophy to screencasts. They slow things down and show how to do things visually, and over the 18+ hours of video included they will show you how to use Rails from the ground up.
Everything about Object Oriented Programming
Everything in Ruby has something or other to do with object oriented programming, these articles will get you started in what you need to know.
Using Attributes
There are two basic things you can do with an object: call a method on it and access an attribute. Ruby doesn't make a distinction between these things, but it does give you some tools to make some methods act like attributes.
Wondering if You Should Overlook The "Require"...
The 'require' method is the reusable code mechanism in Ruby. It allows you to import other source files into your programs.
Mutexes in Ruby
Since we're talking about threads, we have to talk about mutexes.  A Mutex is the only practical way to prevent race conditions (where more than one thread
Ruby on Rails 3 Tutorial: Learn Rails by Example
Ruby on Rails 3 Tutorial: Learn Rails by Example by Michael Hartl is a hands on introduction to not only Ruby on Rails but all the related software and services many Rails developers use such as Git, Github, Heroku and RSpec. There are no long-winded discussions on theory or REST or MVC, each and every part of every chapter is a hands on exercise in building a Rails application. This book is recommended for anyone who prefers a hands on approach to learning.
How to Use String Substitution in Ruby
class="no-js" itemscope itemtype="http://schema.org/Article" > itemprop="description" >Splitting a string
Step 3: Authentication with Devise
Before we get too invested in our blog, we need to set up some authentication. We'll be using the popular and capable Devise gem to handle authentication.
How to Install JSON Gem in Ruby
It's easy to jump into parsing and generating JSON in Ruby with the json gem. It provides an API for parsing JSON from text as well as generating JSON text from arbitrary Ruby objects. It's easily the most used JSON library in Ruby.
How to Use 'OptionParser' for Command Parsing...
Using OptionParser to parse command line options is a preferable alternative to GetoptLong or looking through ARGV manually. But how do you use it?
How to Install Ruby
How to install the Ruby interpreter on Windows, Linux and OS X.
Mapping Arrays
Iterating over arrays isn't the only trick up Ruby's sleeve. Having the ability to map arrays (and other enumerable collections) is a powerful feature.
How Does Ruby Compare to Python?
How do Ruby and Python compare in terms of features, form and function?
Making Deep Copies in Ruby
It's often necessary to make a copy of a value in Ruby. While this may seem simple, and it is for simple objects, as soon as you have to make a copy of a data structure with multiple array or hashes on the same object, you will quickly find there are many pitfalls.
How to Use 'DIR.GLOB' with Directories in Ruby
In the previous article in this series, we discussed the basics of the Dir class. Particularly useful was the Dir.for each method for iterating over all files in a directory. However, this only goes so far. What if you want to iterate over only some files (for example, just XML files) in a directory?
How to Install Ruby's Development Environment...
In the past, the Ruby “One-Click Installer” was the primary choice for installing Ruby on Windows. However, the One-Click Installer fell into disrepair and was eventually abandoned. Something new was needed, and thus, RubyInstaller was born.
A Simple Guide to Using Aliases in Ruby
Aliasing is a powerful Ruby feature that allows more than one method to be referred to by multiple names. This can be used to give a programmer more expressive options or to create copies of a method, allowing you to change the behavior of a class.
Creating Hashes from Arrays
How do you create hashes from tabular data? There are a few ways, but there's a way built into Ruby that fits onto a single line.
Installing RVM on Linux
Installing the Ruby Version Manager (RVM) on Linux
Using the Logger Library--How to Write Log...
How to use the logger library to create and write to log files in Ruby.
Instance Variables
Instance variables are some of the most common and important variables types in Ruby. They begin with the at sign (@) and allow objects to track their internal state.
Instantiation and the Initialize Method
Ruby objects are instantiated using the Class.new method, and initialize using their own initialize methods.
Quick Rails 4 Blog Tutorial
What do you do when a new version of Rails comes out? Build a blog, of course. The blog is kind of the hello, world application of the web application world.
Add a Little Color to Your Shoes
Adding foreground and background colors to your Shoes applications is easy. Shoes has a number of built-in color names that mirror the X11 Color Names used on Linux systems. You can also use HTML-style RGB hex values. Here's how to do it. Page 2.
Install Ruby on Windows
How to install the Ruby interpreter on the Windows operating system.
The 10 Fantastic Free Ways to Learn Ruby
Sometimes the old adage rings true: the best things in life are free. If you've wanted to learn a little Ruby, but haven't been able to fit a programming course into your budget, don't worry. There are a number of places on the Web to begin your learning, without sacrificing money or quality.
Net::SSH--The SSH (Secure Shell) Protocol
Net::SSH is a way for Ruby to interact with SSH (Secure Shell) protocol. It relies on the OpenSSL library for encryption.
Modules: Containment and Composition
Underneath it all, classes are just collections of methods. Ruby implements them using Module, which also have other uses including composition and namespaces.
Getting Started with Bundler
The basics of using Bundler are very trivial, you can be up and running in just a few minutes.
Generating Random Numbers in Ruby
It's often useful in games, simulation and unit testing to generate random numbers, Ruby provides easy access to a pseudo-random number generator.
Optional Method Parameters with Hashes
Using hashes to simulate optional named parameters in methods.
Be Notified of New Twitter Updates by IM
Be notified of Twitter updates by IM, using this Ruby script. It's a pain to switch to a Web browser every you want to check your Twitter account. This script solves that by sending you an instant message (IM) using the Jabber protocol when there's something new to see on Twitter.
Keyword Arguments
Until Ruby 2.0, Ruby has not had true keyword arguments. You could simulate them using a hash, but as of Ruby 2.0 there's no longer any need to do that.
How Use RMV to Install Ruby On OS X Snow Leopard
OS X has pretty easy access to a GCC development environment installed with XCode (an IDE and development
CSV Example: Parsing CSV
A crash course on what CSV is, what it is used for and how it is parsed. A method for parsing CSV files using only Ruby's built-in string methods is presented and discussed.
25 Gem Commands for RubyGems
The gem command is one of the most used Ruby-related commands. This article shows 25 Gem Commands and their functions.
How to Install Gems from Git Repositories in Ruby
How to install gems from git repositories.
Understanding 'String Literals' in Ruby
The basics of strings, string interpolation, single and double quotes, escape sequences and alternate string literal syntaxes. Page 2.
Base64 in Ruby
Base64 is a way to represent any data as ASCII data. Ruby provides a few handy functions to encode and decode Base64.
Can I add empty directories to Git repositories?
Can I add empty directories to Git repositories?
Block Parameters and Yielding
class="no-js" itemscope itemtype="http://schema.org/Article" > itemprop="description" >Block parameters
What is Sinatra?
Sinatra is a web framework. Simply put, it's a library that allows you to write web applications with a minimum of red tape.
Using Git With Ruby on Rails
You don't have to use version control, but you should be. In the past, version control software has been large, clunky, required servers and really was only used when working in groups. But with Git, it's so easy that you really have no excuse, you should be using version control.
Hello, Sinatra! Using Sinatra in Ruby
How to get started in Sinatra, including how to use actions, parameters, ERB and views.
Boolean Operators
While simple boolean expressions will get you pretty far, you'll soon find yourself wanting to act on more than one condition. For that you'll need boolean operators.
RubyMine 5.0
I've always been a Vim person. Just give me a good solid editor and I'll take it from there. But I decided to give RubyMine a good honest try, and here's what I think about it.
Global Variables
Global variables are not often used in Ruby, however, you should at least understand their usage should you ever encounter them.
Cloud Computing and Ruby: Interviewing Hampton...
Why are cloud computing and Ruby on Rails a good match? Let's hear what Hampton Catlin, author of HAML and Wikipedia's head Ruby/mobile architect has to say!
How Does Ruby Compare to the Java Programming...
What features do Ruby and the Java programming language share? How are they alike and how are they different?
What is Ruby?
New to Ruby? Or even to programming? Find out what Ruby really is (and isn't) and why you should (and shouldn't) use it.
What is Cloud Computing?
What is cloud computing? Interviews with industry experts help us define cloud computing, software as service, platform as service and more.
5 Must Know Features of the Ruby Language
If you're going to program in the Ruby language, there are some basic features you absolutely must know. Here are the Top 5.
Step 2: Integrating a Wordpress Theme
The scaffold generator gave us something rather spartan, let's spruce this up by adapting a Wordpress theme to work with our shiny new blog.
Retrieving a Tagged Release
Once you have releases tagged in the repository, it will be useful to retrieve tagged releases. For example, I want to see if a bug was present in version 0.3, so I'll want to retrieve version 0.3 and run it. Git, of course, makes this easy.
What's New in Rails 4?
Now that Rails 4 is out, let's see what's new.
Sending Keystrokes with Win32
Great, now we know how to get to the Win32 API.  Now, on to sending keystrokes using the Win32 API.  Easy, right?  Not really.  It's not that hard, but it's not
Two Dimensional Arrays in Ruby
We'll use a two dimensional array to represent the 2048 game board, but how do we create a 2D array in Ruby?
Constant Variables
class="no-js" itemscope itemtype="http://schema.org/Article" > itemprop="description" >The speed of light
extconf.rb:1:in `require': no such file to load...
Problem: You're trying to install a gem and you encounter an error reading no such file to load -- mkmf. This doesn't always occur, only when you're trying to install gems with native C code that must be compiled.
A Beginner's Guide to Creating a Blog in Ruby
Generating a Rails project from which to build an application.
4 Ways Ruby is Better Than Your Programming...
A comparison of Ruby to other programming languages, including Perl, Java, Python and PHP.
Serialization in Ruby: Marshal
Serializing an object is to convert an object to a byte stream and either store that object for future loading, or sending to another program to be loaded there. There are several common ways to serialize objects in Ruby. The Marshal module is used less often than the other methods, but it's included in the standard library.
Creating and Distributing Gems with Bundler
Creating Ruby gems has always been a bit of a pain. When you get right down to it, it's not a hard thing to do, but it's easy to forget how if you don't do it often enough. There are quite a few gems to help you write other gems, but if you're using Rails 3, there's already a gem on your system that does this: Bundler.
Iterating Over Strings
It's not a very common thing in Ruby. You have more sophisticated string tools (such as split or scan), but there are times when you'd want to iterate over the characters in a string. Unicode complicates this matter, but Ruby makes it simple.
undefined method `to_sym' for nil:NilClass
Problem: Seemingly at random, you've encountered the error undefined method `to_sym' for nil:NilClass, or a similar error message for any method name other than to_sym.
How to Use and Create Blocks in Ruby
How to use blocks in Ruby.
Adding and Installing Gems from the Ruby Gems...
Learn to search the Ruby Gems repository to find gems to add and install to your library.
Net:SSH--Executing Programs with Net::SSH
Running programs with Net::SSH is simple enough. The Session object gives you two convenient methods with which to accomplish this task.
What is Rack?
There’s a lot of talk about Rack , but unless you’re a framework author yourself, you rarely see it. So what is Rack? And why, as an application developer, should you care about it?
What is Bundler?
Bundler is a gem dependency manager for Ruby.
What's New in Ruby 1.9.1? -The Lambda Operator
Among the new features in release of Ruby 1.9.1 is the Lambda operator, a shortcut used to make nameless methods. Learn how to use this feature introduced in Ruby 1.9.1.
Making a Text Adventure Game in Ruby
Text adventure games were a very popular game genre on minicomputers and microcomputers from the 1970's through the 1990's. This article series will take you through each step of making a text adventure game in Ruby.
Part 3: Implementing
In this part, we'll implement a complete working application.
Load Vs. Require
You probably know about the 'require' method (yes, it is a method, it's not a keyword), but what about the 'load' method? What's so different about it?
Rails Blog Tutorial - Allowing Comments
Part four of the Ruby on Rails blog tutorial shows you how to create a comments table to allow users to comment on your blog posts.
Sorting Arrays
One of the most common tasks when dealing with arrays is to sort them. Luckily, Ruby makes this simple and flexible.
Riding Shotgun with Sinatra
Now that you can write controller logic and views and Haml, you can start putting together some more complex application. There's one very annoying thing though: Sinatra does not reload its code whenever you make a change. If you make a change, you have to stop and restart the server. This is just an extra step and generally an annoyance. This where shotgun comes in.
Eval: Running Code on the Fly
Most non-compiled languages have some kind of eval function, which will take a string and execute it as code.
How to Use the Twitter Gem for Ruby
Using the Twitter RubyGem, making API requests to Twitter is even easier than using the twitter method.
What is Ruby on Rails?
Learn about the concepts of Ruby on Rails, a Model-View-Controller framework for creating database-driven websites in Ruby.
Using Temporary Files
There are many hidden pitfalls when using temporary files. Ruby's Tempfile class solves many of these.
NoSQL and Document Oriented Databases
Chances are, you've spent your entire database life with relational databases. Data gets organized into columns, and stored in rows. You manipulate data with SQL (Structured Query Language) and there's really no other way to do it. There are competing SQL servers out there (MySQL, SQLite, etc), but they all more or less operate in the same way. But there's much more out there than SQL databases, especially with all the new software in the past few years.
Using Haml with Sinatra
How to use Haml to create Sinatra views and layouts. Page 3.
Using RVM Gemsets
One of the most powerful, useful and often overlooked features of RVM is the gemset. A gemset is a separate gem directory, so the gems in one gemset don't conflict with the gems in another gemset.
Overlooking Input and Output? Using the Input /...
Input and output methods are often overlooked by many Ruby programmers. How often have you used the <b>gets</b> and <b>puts</b> methods without giving them a second glance? Learn all the features of these methods to better put them to use in your code.
Using Rack
In the previous article, you learned what Rack is. Now, it’s time to start using Rack and serve up some pages.
Named Regexp Groups
Ruby 1.9 introduces the concept of a named capture group. These named groups can be defined at the beginning of a regexp statement using a trick that tells for the regexp engine to look for exactly 0 instances of the group. Later, the group can be recalled using the \g element, followed by the name of the group. You can think of named capture groups as subroutines inside of a regular expression.
Cryptographic Hashes in Ruby
Generating cryptographic hashes in Ruby is quite easy. Ruby provides both a built in method and gives access to OpenSSL's hashing algorithms in most installations.
Working with Directories
Learning how to work with files is one of the first things new Ruby programmers learn. However, how to work with directories of files is something that's often skipped or only lightly touched upon. Ruby does have some powerful mechanisms for working with directories though.
A New Rails Project
Before you can start making models, views and controllers for your web application, you need to generate a new applications. Rails projects are too complex to create by hand, you really do need an empty project to bootstrap you. It's not hard though, there's really only one command you need to know.
Adding Files to a Repository
How to add files to a Git repository.
Using the Enumerable Module
By using the Enumerable module, you can make any of your classes act like Ruby standard collections. All you need to do is implement the 'each' method.
How Does Ruby Compare to Perl?
How do Ruby and Perl compare in function and form?
Buttons and Submitting Forms
class="no-js" itemscope itemtype="http://schema.org/Article" > itemprop="description" >Buttons primarily
Quick Tip: Install Gems Faster
Some larger projects, especially Ruby on Rails, come with quite a bit of documentation. This is good, documentation is good, but the code that processes this documentation (RDoc) into HTML and ri format is not exactly speedy. On slower computers, or with larger projects, the time this takes becomes and annoyance.
How Can I Store Key/Value Pairs in Ruby?
Storing key/value pairs in Ruby doesn't always need to be accomplished by using a hash. You can also use the Struct and OpenStruct classes.
Update Twitter From an RSS Feed
This Ruby script for Twitter is what's often referred to as a "mashup." Mashups interface one protocol
Everything You Need to Know About Variables
Variables are named references to objects in memory. Their several variants (local, instance, class, constant, etc) each have their own subtleties.
Class Variables
Class variables in Ruby are more or less as you'd expect form an object oriented language. However, Ruby throws you a curveball you can use to your advantage.
How to Install and Use Ruby's Tk Toolkit
Directions of how to install the Tk GUI and its Ruby bindings on Windows, Linux and Mac OS X.
The ‘exec’ Method
There are several ways to run other programs in Ruby. There is the system> method, backticks, etc. However, they all spawn new processes. If there is nothing left for your Ruby program to do, it has to sit there wasting memory until the launched program finishes. The exec> method fixes this.
Router Basics
The Ruby on Rails router is responsible for determining which action to run depending on the HTTP request type and URL passed by the web server.
RVM and 'sudo'
RVM is great. However, there may be times where you must run Ruby scripts with RVM as root (or another user) via sudo.
Loops
Ruby has a the usual and expect loops, as well as a number of loops specific to Ruby. It even has a way to define you own types of loops.
How to Display Your Ruby Version in Your Bash...
With RVM installed on your system, it's easy to have many versions of Ruby installed. And, especially if you switch between them often, it's easy to forget which Bash command prompt is using which Ruby version. You can solve this by putting your Ruby version in your Bash prompt.
Running the Ruby Profiler
Running the Ruby profiler to determine which methods are most expensive and which need to be optimized.
Reading Files
Ruby programs rarely exist in their own little world. And while many choose to communicate over the internet, there's still plenty of need to access plain old files.
A Quick Introduction to DataMapper
class="no-js" itemscope itemtype="http://schema.org/Article" > itemprop="description" >DataMapper is
AJAX With Sinatra
In this article we take a look at how to use jQuery and Sinatra to implement an AJAX interface.
Constants in Ruby
Like just about every programming language every conceived, Ruby supports constants. A constant is a variable whose value cannot be changed. However, in Ruby, this has some caveats.
What is RVM?
RVM is the Ruby Version Manager. It allows you to install and manage several different versions and implementations of Ruby on one computer, including the ability to manage different sets of RubyGems one each.
Click Blocks and Animation
Now that you know how to use the animate method , you can create a crude timer application. A timer application
Step 1: Scaffolding Posts
Without a framework like Rails, and particularly the scaffold generator, getting up and running with any project was a pain. You'd be doing a lot of configuring and planning and typing out all the methods to create blog posts and interact with the database. Rails does all this in just a few commands, and while it's not something you'll want to deploy right away, it does give you an excellent starting point.
The Algorithm
Before we start coding, we take some time to look at the game of 2048.
Installing Ruby on Rails on OS X
While Apple does include both Ruby and Ruby on Rails by default with OS X, you'll need to install newer versions. This is a bit of a process, but thankfully you'll only need to get through this just once.
Installing Gosu
While Gosu does require native compilation, the developers thankfully require pre-compiled packages for all platforms. On Windows, Linux and OS X, Gosu can be installed with a single gem command.
Why JRuby?
As a Rubyist you probably know and love the official Ruby implementation. It's very stable and capable, so why should you use JRuby?
Installing Ruby on Rails on Windows
Installing Ruby, Rails and the few other things you'll need way always a pain on Windows. It's just not a very friendly environment for the task. But fear not, the guys at EngineYard have made RailsInstaller, and this task is braindead simple and will be done in minutes.
Visual Tutorial: Installing Ruby on Windows
A visual walkthrough on installing Ruby on Windows. Page 7.
Listing Known Rubies
class="no-js" itemscope itemtype="http://schema.org/Article" > itemprop="description" >In RVM-speak,
Check Email With Ruby
Learn to use Ruby's pre-installed POP3 libraries to check your email.
protect_from_forgery
A feature in Rails that protects against Cross-Site Request Forgery (CSRF) attacks.
Getting Information About a File in Ruby Using...
Sometimes blindly opening files just won't cut it, sometimes you need to know more information about a file before opening it.
Part 4: Integrating Devise
Now that we have Devise installed, it's time to integrate it into the application.
How to Install 'Git' on Windows
Installing command line tools such a Git on Windows is often difficult. Not only do you have to find a Windows port or attempt to compile the tool yourself from C source code, you also have to deal with the Windows command line. The Windows command line is, to say the least, a little lacking. Windows users are in luck here though, the MSysGit project solves both these problems.
Can't Modify Frozen String
I'm trying to modify a frozen string, but I keep getting this exception. Why?
Practical Ruby Projects: Ideas for the Eclectic...
A review of the book Practical Ruby Projects: Ideas for the Eclectic Programmer by Topher Cyll from Apress.
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