Ruby: Most Popular Articles
Problem: You encounter an error reading NameError: uninitialized constant Something or NameError: uninitialized constant Object::Something (with various class names in place of Something).
Use command-line arguments to pass parameters to your Ruby scripts from the command line.
This article explains and teaches how to use a associative arrays (hashes) as a way to store multiple variables in one data structure.
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.
This article explains and teaches how to use a arrays as a way to store multiple variables in one data structure.
Using environment variables 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.
Loops, including while and include loops, are one of the most commonly used constructs in computer programs. Page 2.
How to check POP3 email accounts in Ruby.
Use comments to annotate your Ruby code.
String manipulation using the split method in Ruby. Split strings into a list of substrings.
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.
How to install Ruby on the Linux operating system.
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.
What type of language is the Ruby programming language?
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.
Using and manipulating strings and substrings in Ruby. Page 4.
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.
Problem: You encounter an error reading NameError: undefined local variable or method `a' for #
class="no-js" itemscope itemtype="http://schema.org/Article" > itemprop="description" >Splitting a string
How to use the command line interface on Windows, Linux and OS X to run Ruby scripts and use the interactive Ruby program.
How to use the logger library to create and write to log files in Ruby.
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.
Using OptionParser to parse command line options is a preferable alternative to GetoptLong or looking through ARGV manually. But how do you use it?
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.
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?
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.
The main loop is the heartbeat of any game, and is the first thing you need to learn to start making your own games.
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.
The 'require' method is the reusable code mechanism in Ruby. It allows you to import other source files into your programs.
class="no-js" itemscope itemtype="http://schema.org/Article" > itemprop="description" >The ternary (or
It's often useful in games, simulation and unit testing to generate random numbers, Ruby provides easy access to a pseudo-random number generator.
Ruby objects are instantiated using the Class.new method, and initialize using their own initialize 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.
Installing the Ruby Version Manager (RVM) on Linux. Page 2.
Net::SSH is a way for Ruby to interact with SSH (Secure Shell) protocol. It relies on the OpenSSL library for encryption.
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.
We'll use a two dimensional array to represent the 2048 game board, but how do we create a 2D array in Ruby?
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.
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 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.
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.
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.
The basics of using Bundler are very trivial, you can be up and running in just a few minutes.
Part one of the Ruby on Rails blog tutorial focuses on creating a Rails project and scaffolding a basic blog post data structure.
How do Ruby and Python compare in terms of features, form and function?
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.
Can I add empty directories to Git repositories?
The basics of strings, string interpolation, single and double quotes, escape sequences and alternate string literal syntaxes. Page 2.
If you're going to program in the Ruby language, there are some basic features you absolutely must know. Here are the Top 5.
What is cloud computing? Interviews with industry experts help us define cloud computing, software as service, platform as service and more.
How to install the Ruby interpreter on Windows, Linux and OS X.
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.
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.
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.
Using hashes to simulate optional named parameters in methods.
The gem command is one of the most used Ruby-related commands. This article shows 25 Gem Commands and their functions.
How to get started in Sinatra, including how to use actions, parameters, ERB and views.
What features do Ruby and the Java programming language share? How are they alike and how are they different?
A comparison of Ruby to other programming languages, including Perl, Java, Python and PHP.
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.
In this part, we'll implement a complete working application.
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.
If you're coming from a compiled language, it's easy to think that method calls are like native function calls. This is simply not the case in Ruby.
Global variables are not often used in Ruby, however, you should at least understand their usage should you ever encounter them.
What does a + b mean? That all depends on what 'a' is. Ruby allows you to define a number of arithmetic operators and they're called on the left-hand side of any such expression.
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.
class="no-js" itemscope itemtype="http://schema.org/Article" > itemprop="description" >Block parameters
Running programs with Net::SSH is simple enough. The Session object gives you two convenient methods with which to accomplish this task.
class="no-js" itemscope itemtype="http://schema.org/Article" > itemprop="description" >The speed of light
There's a really quick way to get the result of the last expression evaluated in IRB.
How to install the Ruby interpreter on the Windows operating system.
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.
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.
One of the most common tasks when dealing with arrays is to sort them. Luckily, Ruby makes this simple and flexible.
Digraphs are extremely useful for hierarchical data visualization. However, they're not very easy to generate yourself. This is where Graphviz and the Graph gem come in.
In the previous article, you learned what Rack is. Now, it’s time to start using Rack and serve up some pages.
Directions of how to install the Tk GUI and its Ruby bindings on Windows, Linux and Mac OS X.
Using the Twitter RubyGem, making API requests to Twitter is even easier than using the twitter method.
Thread pools are a common pattern in many programs: the need to run M tasks, but only wish to run N of them in parallel at a time.
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!
A review of the book Practical Ruby Projects: Ideas for the Eclectic Programmer by Topher Cyll from Apress.
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.
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 blocks in Ruby.
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.
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.
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.
Base64 is a way to represent any data as ASCII data. Ruby provides a few handy functions to encode and decode Base64.
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.
How do do various types of URL matching in Sinatra.
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.
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.
How to install gems from git repositories.
Much is made of the two base data structures in Ruby: the Array and the Hash. However, it's also quite easy to use two dimensional arrays in Ruby.
As with most flavors of Ruby, the easiest, cleanest and least painful way to install jRuby is with RVM, the Ruby Version Manager. And although jRuby is different than MRI, the official Ruby interpreter, it can be installed just as easily, arguably easier. Page 2.
Before we start coding, we take some time to look at the game of 2048.
Now that Rails 4 is out, let's see what's new.
Now that you have Linux up and running, and you have Ruby, time to add the two most essential parts of any Rubyist's toolbox: version control and a good editor. Page 3.
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.
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 do Ruby and Perl compare in function and form?
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?
Learn to search the Ruby Gems repository to find gems to add and install to your library.
Sinatra is a web framework. Simply put, it's a library that allows you to write web applications with a minimum of red tape.
So, you've gotten your shiny new Mac and you want to get right into Ruby programming , where how do you
Quickly Run an HTTP Server with Ruby (Also, the Un Library)
Is Ruby a good first language to learn? Everyone has to start somewhere, and is Ruby an appropriate place to start if you're looking to take the plunge and learn a programming language?
RVM is great. However, there may be times where you must run Ruby scripts with RVM as root (or another user) via sudo.
class="no-js" itemscope itemtype="http://schema.org/Article" > itemprop="description" >Buttons primarily
The principles of Agile Development and how agile applies to Ruby on Rails.
Exploring and knowing the Twitter API is fine, but what do you do from there? Here are 3 practical scripts to help you follow followers on Twitter, update your Twitter account via an RSS feed and to be notified of your friend's new Tweets as they come in.
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?
Learn about the concepts of Ruby on Rails, a Model-View-Controller framework for creating database-driven websites in Ruby.
Running the Ruby profiler to determine which methods are most expensive and which need to be optimized.
How to use Haml to create Sinatra views and layouts. Page 7.
Bundler is a gem dependency manager for Ruby.
Distributed Ruby, or DRb, is a library that allows you to communicate with remote Ruby objects and programs, using TCP/IP network protocols.
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.
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.
class="no-js" itemscope itemtype="http://schema.org/Article" > itemprop="description" >In order to analyze
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.
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.
A visual tutorial with screenshots showing how to install the Rubygame library on Windows, including installing all needed DLL files. Page 4.
Most non-compiled languages have some kind of eval function, which will take a string and execute it as code.
Sometimes blindly opening files just won't cut it, sometimes you need to know more information about a file before opening it.
class="no-js" itemscope itemtype="http://schema.org/Article" > itemprop="description" >Most likely, you'll
Note that this application is not accurate. The complete version contains some extra code that does time
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.
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 literal is an object that can be constructed using special syntax.
SSH is not just for running commands, it's a general conduit for encrypted communications between two hosts. One common use for SSH is to transfer files using the SCP protocol over SSH. You can use SCP in your Ruby programs with the Net::SCP library, which is a supplement to Net::SSH. Page 2.
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.
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.
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.
A number guessing game is written, and each of its features explored.
Exceptions are used to handle things the unexpected things that might go wrong with your Ruby code. This article addresses what Exceptions are and how they can be used.
JSON is a data serialization format for communicating between applications. It's a text format that features a lightweight syntax and closely mirrors the common data structures in modern programming languages.
I declared a variable in the global scope, and now I can't access it. What's going on here?
There are many hidden pitfalls when using temporary files. Ruby's Tempfile class solves many of these.
There are multiple ways of installing Git on Linux. Depending on which Linux distribution you're using and whether it provides binary packages for Git, you can either install a binary package or install from source.
The syntax of a language is the grammatical rules a program must follow in order to be understood by the interpreter or compiler.
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.
I'm trying to modify a frozen string, but I keep getting this exception. Why?
Methods are very important in Ruby. You have probably used them before, but have you thought about how to really define them?
Ruby is an object oriented programming language. This means code is organized into classes, and data is manipulated via objects. Since this is so essential to Ruby, it's very easy to do.
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.
comes in. The Heroku Hacker's Guide doesn't aim to be a complete reference (and since cloud computing
Hashes aren't just data structures, they have a few tricks up their sleeves. And while you may never end up using any of these tricks, they really show off how flexible the Hash class is.