Ruby Codeacademy Learnings Notes

• Ruby file extension script*.rb*

• Commenting two types of comments
  Single line comments
  start with a #.
  Multi line comments start with =begin and end with =end.

• put and print commands can be used to display text in the console

• Variables: There are four different types of variables in Ruby
  Local variables
  must begin with a lowercase letter or _. These variables are local to the code block of the method they are declared in.
  Instance Variables
  Instance variables begin with an @ symbol. Instance variables are variables that belong to an object.
  Class Variables
  Class variables begin with an @@ sign. Class variables are available across different objects shared by all the descendants of the class. They must be initialized before use.
  Global Variables
  Global variables begin with an $ symbol. While Class variables are not available across different classes, global variables are. Its scope is global, meaning that it can be accessed from anywhere in the program.

• Object Methods
  everything in Ruby is an object, are built-in abilities of objects. To access an object’s methods, you need to call it using a . and the method name.
  example: # Method to get the string reversed
  print var*.reverse*
  # ymedacedoc
  .length Ruby will return the length of the string (that is, the number of characters—letters, numbers, spaces, and symbols).
  .upcase and .downcase
  returns a version of the string in all uppercase or all lowercase

  example: name = "Jamie"
  puts name*.downcase.reverse.upcase*
  # EIMAJ

• Strings
  single quotation marks (‘’) or double quotation marks (“”)

• string interpolation
  used to insert the result of Ruby code into a string
  example: age = 30
  print "I am #{age} years old"
  # "I am 30 years old"

• Get user input in Ruby
  using gets.chomp
  gets is the method used to retrieve user input.
  Ruby automatically adds a new line after each bit of input, so chomp is used to remove that extra line.
  example: print "Type your name and press Enter: "
  name = gets.chomp
  puts "My name is #{name}!"

• Modulo
  returns the modular value, the remainder, when two numbers are divided.
  example: puts 5*.modulo(3)
  # Output: **2*
  5 is divided by 3 and the remainder is 2

• User input Simple Program:
  print "What's your first name? "
  first_name = gets.chomp
  first_name.capitalize!

print "What's your last name? "
last_name = gets.chomp
last_name.capitalize!

puts "Your name is #{first_name} #{last_name}!"