Ruby code snippets

ruby-snippets.rb

#!/usr/bin/ruby
# shebang (#!) must on the first line of the script in order to run this
# with `./script.rb` rather than `ruby script.rb`
# use `whereis ruby` to find the path

# single line comments

=begin
  Multi-line comments.
  Begin and End must be on the first
  column of the file.
=end

heredoc = <<END
A really long
multi-line
string
END

puts heredoc

puts "Hello, World!"

status = true

_new_status = false

status = _new_status

# A constant starts with an uppercase letter. If created outside a class,
# it's available everywhere. Note that it CAN be changed, though!
Legit = true

__not_legit = false

puts "Variables can only start with characters and underscores."

puts "Instance variables start with @, class variables start with @@, and global variables start with $."

# `puts` automatically adds a newline
print "Print does not output newlines automatically"
print ", as puts does."
print "\n"

# print "Give me input: "
# num = gets
# puts "Your input was: " + num

# Object is the parent class of all Ruby classes
# Kernel is a Ruby module, and is included in Object
# A Module is like a class, but you can't instantiate it
# You can add a Module to a Class in order to get access to all its methods

# Types (boolean, integer, float, array, hash)
# Boolean
flag = true

# Integer
num = 3

# Float
pi = 3.14

# String
# Single or double quotes work
quote = '"Syntax is the hobgoblin of tiny developer minds -- @cndreisbach."'

# Array
cities = ["Charlotte", "Raleigh"]

# Hash
states = { "NC" => "North Carolina", "SC" => "South Carolina" }

puts "Use kind_of? to see a variable's type. 'pi' is a Float: #{pi.kind_of? Float}"
puts "Use class to see a variable's class: #{cities.class}"
puts "Use inspect to get a string version of an array or hash: #{states.inspect}"