Ruby Quick Reference

# Single line comment

# Multiple
# line
# comment

stuff = "stuff"

"Single line string"

# Old style - Ruby < 2.3 keep white space preceding string.
stuff = <<-DOC
  Stuff and thing.
  More stuff and things
DOC
#=> "  Stuff and thing.\n  More stuff and things\n"

# Squiggly line style - Ruby >= 2.3 strips preceding white space
stuff = <<~DOC
  Stuff and thing.
  More stuff and things
DOC
#=> "Stuff and thing.\nMore stuff and things\n"

:stuff

42

true

# or

false

["stuff", "things"]

# Old syntax - Ruby < 1.9
{:stuff_key => "stuff_value", :things_key => "things_value"}

# New syntax - Ruby >= 1.9
{stuff_key: "stuff_value", things_key: "things_value"}

# Iterate array with a block
things.each do |thing|
  puts "#{thing}"
end

# One line block syntax for short code blocks
things.each {|thing| puts "#{thing}"}

# Iterate hash
stuff.each do |key, value|
  puts "#{key} #{value}"
end

i = 1
while i < 42 do
  puts(i)
  i += 1
end

if 1 > 42
  puts "One"
elsif 42 < 1
  puts "The answer"
else
  puts "Maths is fun"
end

def stuff
  # The last element in a function is returned automatically
  ["stuff", "more stuff", "other stuff"]
end

class StuffAndThings
  attr_reader :stuff # Getter only
  attr_writer :things # Setter only
  attr_accessor :blah # Getter and Setter
  def initialize(stuff, things, blah)
    @stuff = stuff
    @things = things
    @blah = blah
  end
end