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Tag Archives: ruby
Private Member Variables in Ruby
How can you create private member variables in Ruby? If you’re used to the attr_accessor helper, that won’t work–that makes your member variables public. You can use the @ notation, eg. @variable_name. (Attr_accessor just gives you free getters and setters.) Continue reading
Conditional Code
You’re writing some code for a new client. Debug statements litter the code. Oops, you sent that to the client. Oops, you’re printing out credit-card numbers. Identity theft ensues. Don’t move to Mexico–you can actually handle this problem in an elegant way by using conditional code statements INSIDE your class … Continue reading
String Replacement in Ruby
How can you replace strings in Ruby? There are a couple of options; there’s the tr function, which takes two sets of characters, and substitutes them; and there’s the gsub method, which makes a global replacement based on a regular expression. Powerful stuff! Continue reading
Ruby Command-Line Arguments
How can you access command-line arguments in Ruby? Through the special array called ARGV. It’s a zero-indexed array of your command-line arguments; so ARGV[0] is the first, ARGV[1] is the second, and so on. You can use ARGV.length to get the number of arguments, too. Continue reading
Chaining Array Appends With <<
In Ruby, you can push an element to an array using the << method. This method returns the array, so you can chain appends using it, like so: a << "One" << "Two". Nice! Continue reading
Exception and Error Handling
A lot of programming languages have an error-catching (or exception-handling) mechanism, where you can trap errors. How do we do this in Ruby? There are two keywords: begin, and rescue; and the ancestor of all errors is called StandardError. Continue reading
Ruby Interactive Prompt
The great “try ruby!” online interactive prompt is broken! How can we write some code that runs almost the same, albeit in a local Ruby environment? A few minutes of experimentation revealed this little snippet, which works fairly well. Continue reading
Functions as First-Class Objects
A lot of programming languages have functions as first-class objects (you can pass them around, execute them, etc.) Ruby has some sort of functionality like that (proc and functors and yield, oh my!), but there’s a simpler solution: the (albeit abusable) eval method. Continue reading
Page Rendering Time
A lot of websites show the page rendering time at the bottom. How can we implement this in our Rails website? We discuss a simple approach, where you wrap between two calls to Time.now (to get the current time). Subtracting them yields the time difference, in fractional seconds. Continue reading
Block Comments in Ruby
How do you comment out a chunk of code? Other programming languages (C++, Java, etc.) have a slash-star style of block comments, like so: /* */ … but what about Ruby? Does Ruby have a mechanism for this, too? The answer is YES; BUT, there’s a catch! If you don’t watch whitespace … Continue reading →