Ruby: Most Popular Articles
This article explains and teaches how to use a arrays as a way to store multiple variables in one data structure.
Problem: You encounter an error reading NameError: uninitialized constant Something or NameError: uninitialized constant Object::Something (with various class names in place of Something).
This article explains and teaches how to use a associative arrays (hashes) as a way to store multiple variables in one data structure.
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 is the heartbeat of any game, and is the first thing you need to learn to start making your own games.
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.
Use command-line arguments to pass parameters to your Ruby scripts from the command line.
Using environment variables in Ruby.
Loops, including while and include loops, are one of the most commonly used constructs in computer programs. Page 2.
String manipulation using the split method in Ruby. Split strings into a list of substrings.
Use comments to annotate your Ruby code.
class="no-js" itemscope itemtype="http://schema.org/Article" > itemprop="description" >The ternary (or
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.
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.
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.
What type of language is the Ruby programming language?
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.
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.
How to install Ruby on the Linux operating system.
How to use the command line interface on Windows, Linux and OS X to run Ruby scripts and use the interactive Ruby program.
Using and manipulating strings and substrings in Ruby. Page 4.
Problem: You encounter an error reading NameError: undefined local variable or method `a' for #
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 in Ruby has something or other to do with object oriented programming, these articles will get you started in what you need to know.
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.
The 'require' method is the reusable code mechanism in Ruby. It allows you to import other source files into your programs.
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 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.
class="no-js" itemscope itemtype="http://schema.org/Article" > itemprop="description" >Splitting a string
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.
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.
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 the Ruby interpreter on Windows, Linux and OS X.
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 do Ruby and Python compare in terms of features, form and function?
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.
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?
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.
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.
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 the Ruby Version Manager (RVM) on Linux
How to use the logger library to create and write to log files in Ruby.
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.
Ruby objects are instantiated using the Class.new method, and initialize using their own initialize methods.
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.
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.
How to install the Ruby interpreter on the Windows operating system.
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 is a way for Ruby to interact with SSH (Secure Shell) protocol. It relies on the OpenSSL library for encryption.
Underneath it all, classes are just collections of methods. Ruby implements them using Module, which also have other uses including composition and namespaces.
The basics of using Bundler are very trivial, you can be up and running in just a few minutes.
It's often useful in games, simulation and unit testing to generate random numbers, Ruby provides easy access to a pseudo-random number generator.
Using hashes to simulate optional named parameters in methods.
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.
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.
OS X has pretty easy access to a GCC development environment installed with XCode (an IDE and development
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.
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.
The basics of strings, string interpolation, single and double quotes, escape sequences and alternate string literal syntaxes. Page 2.
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?
class="no-js" itemscope itemtype="http://schema.org/Article" > itemprop="description" >Block parameters
Sinatra is a web framework. Simply put, it's a library that allows you to write web applications with a minimum of red tape.
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.
How to get started in Sinatra, including how to use actions, parameters, ERB and views.
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.
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 are not often used in Ruby, however, you should at least understand their usage should you ever encounter them.
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!
What features do Ruby and the Java programming language share? How are they alike and how are they different?
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? Interviews with industry experts help us define cloud computing, software as service, platform as service and more.
If you're going to program in the Ruby language, there are some basic features you absolutely must know. Here are the Top 5.
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.
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.
Now that Rails 4 is out, let's see what's new.
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
We'll use a two dimensional array to represent the 2048 game board, but how do we create a 2D array in Ruby?
class="no-js" itemscope itemtype="http://schema.org/Article" > itemprop="description" >The speed of light
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.
Generating a Rails project from which to build an application.
A comparison of Ruby to other programming languages, including Perl, Java, Python and PHP.
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 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.
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.
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 blocks in Ruby.
Learn to search the Ruby Gems repository to find gems to add and install to your library.
Running programs with Net::SSH is simple enough. The Session object gives you two convenient methods with which to accomplish this task.
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?
Bundler is a gem dependency manager for Ruby.
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.
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.
In this part, we'll implement a complete working application.
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?
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.
One of the most common tasks when dealing with arrays is to sort them. Luckily, Ruby makes this simple and flexible.
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.
Most non-compiled languages have some kind of eval function, which will take a string and execute it as code.
Using the Twitter RubyGem, making API requests to Twitter is even easier than using the twitter method.
Learn about the concepts of Ruby on Rails, a Model-View-Controller framework for creating database-driven websites in Ruby.
There are many hidden pitfalls when using temporary files. Ruby's Tempfile class solves many of these.
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.
How to use Haml to create Sinatra views and layouts. Page 3.
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.
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.
In the previous article, you learned what Rack is. Now, it’s time to start using Rack and serve up some pages.
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.
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.
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.
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.
How to add files to a Git repository.
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 do Ruby and Perl compare in function and form?
class="no-js" itemscope itemtype="http://schema.org/Article" > itemprop="description" >Buttons primarily
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.
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.
This Ruby script for Twitter is what's often referred to as a "mashup." Mashups interface one protocol
Variables are named references to objects in memory. Their several variants (local, instance, class, constant, etc) each have their own subtleties.
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.
Directions of how to install the Tk GUI and its Ruby bindings on Windows, Linux and Mac OS X.
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.
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 is great. However, there may be times where you must run Ruby scripts with RVM as root (or another user) via sudo.
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.
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 to determine which methods are most expensive and which need to be optimized.
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.
class="no-js" itemscope itemtype="http://schema.org/Article" > itemprop="description" >DataMapper is
In this article we take a look at how to use jQuery and Sinatra to implement an AJAX interface.
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.
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.
Now that you know how to use the animate method , you can create a crude timer application. A timer application
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.
Before we start coding, we take some time to look at the game of 2048.
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.
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.
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, 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.
A visual walkthrough on installing Ruby on Windows. Page 7.
class="no-js" itemscope itemtype="http://schema.org/Article" > itemprop="description" >In RVM-speak,
Learn to use Ruby's pre-installed POP3 libraries to check your email.
A feature in Rails that protects against Cross-Site Request Forgery (CSRF) attacks.
Sometimes blindly opening files just won't cut it, sometimes you need to know more information about a file before opening it.
Now that we have Devise installed, it's time to integrate it into the application.
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.
I'm trying to modify a frozen string, but I keep getting this exception. Why?
A review of the book Practical Ruby Projects: Ideas for the Eclectic Programmer by Topher Cyll from Apress.