All Ruby syntaxes¹ that represent the R string literal: (1) Double Quoted Literal "R" (1) Single Quoted Literal 'R' (1) Single Char Literals ?R (9) Heredocs <<"STRING" R STRING <<'STRING' R STRING <<STRING R STRING <<-"STRING" R STRING <<-'STRING' R STRING <<-STRING R STRING <<~"STRING" R STRING <<~...

There are two very different ways to create local variables in Ruby. You are probably familiar with the classical way: a, b = "$", "€" a # => "$" b # => "€" It is simple to understand and looks good. But Ruby would not be Ruby, if there weren't for more obscure ways to assign variables: You could re...

Ruby puts a lot of effort into its Enumerable module, offering a lot of different ways of iterating through collections. It is one of the reasons for Ruby's success, but you can also call it idiosyncratic, sometimes. This episode portraits enumerables' three handy slice_* methods. Slicing Enumerable...

Some of IRB's command-line options can be called idiosyncratic as well. Take math mode¹ as an example: It will require the infamous mathn library on start up: $ irb -m >> Math #=> CMath >> 3/2 #=> (3/2) >> !!defined?(Vector) #=> true ¹ Math mode actually has been removed in Ruby version 2.5 And anot...

You are here for a collection of 10 advanced features of regular expressions in Ruby! Regex Conditionals Regular expressions can have embedded conditionals (if-then-else) with (?ref)then|else. "ref" stands for a group reference (number or name of a capture group): # will match everything if string c...

Ruby's ENV object gives you access to environment variables. It looks like normal Ruby hash: ENV["TERM"] #=> "xterm" ENV["SOMETHING"] = "NEW" #=> "NEW" But this is only the surface. Turns out ENV is a special object: ENV.class #=> Object It is hash-like, but lacks some functionality: ENV.flatten # N...

This is an overview of all the special, two-letter (and other) global variables in Ruby, which Ruby inherited from Perl. For the purpose of improving code readability, Ruby comes with English.rb in its standard library (or Deutsch.rb as gem), which provides non-cryptic aliases and some documentation...

One of the never-ending style battles in Ruby land is module_function vs extend self. Both enable you to define module methods, which can be called not only from instance level, but also from class level. This enables you to make modules that can optionally be include'd into your current scope, whic...

There is a command-line switch to enable command-line switches: -s Enables some switch parsing for switches after script name but before any file name arguments (or before a --). Any switches found there are removed from ARGV and set the corresponding variable in the script. In this context "corresp...

There is a one-liner on the internet that will start a local web server, for serving all the static files in your current directory: $ python -m SimpleHTTPServer 8080 Or with Python 3: $ python3 -m http.server Rubyists generally do not want to rely on Python, so there is a Ruby equivalent: $ ruby -r...

The script lines feature is probably the most famous example for idiosyncratic naming in Ruby! Ruby can save all source files you load or require as strings. This is useful for debugging utilities, for example, standard library's debug and tracer both use these capabilities. This is possible with th...

a A b B c C d D e E F g G h H l L m m0 M n N p P q Q s S u U v V w x X Z @ ! * < > _ Ruby comes equipped with a powerful option for low level string manipulation: String#unpack and its counter part Array#pack. Today's episode takes a closer look. The general way how String#unpack is used is this: "a...

Ruby has some ways to turn on debug mode, which library authors can use to print out extra information for interested users. But unfortunately, there are multiple debug modes in Ruby. When to use which one? Consider you have this code: def production_method puts "I am doing the right thing part 1" #...

Ruby strings are powerful. You could say Ruby is built around manipulating strings. There are tons of ways how to work with strings and as of Ruby 2.7.1 String offers 130 instance methods. Knowing them well can save you a lot of time. What follows is a list of 10 lesser known things about strings: S...

Compared to other languages, Ruby does not have very good tool support for development. This might not be a problem for many of us: In the end, humans create the code, and not the tools. Nevertheless, it would be great to have better tools. Or at least valid syntax highlighting! The following table ...