Programming basics

basics.rb

"Ricardo" #=> String
4         #=> Integer
4.6       #=> Float
[1,2,3]   #=> Array
(1..10)   #=> Range

false     #=> FalseClass (Boolean)
true      #=> TrueClass (Boolean)
nil       #=> NilClass

name = "Ricardo"
name.upcase

# Print the result of 5 + 6 to the terminal
puts 5 + 6

puts name # "Ricardo" "RICARDO"

methods.rb

# DRY (Don't Repeat Yourself)!!!!!
# puts "Hello Ricardo, how are you?"
# puts "Hello Fabi, how are you?"
# puts "Hello Hanna, how are you?"
# puts "Hello José, how are you?"

# method definition (the code inside WON'T RUN until
# the method is called!)
# def greet_person
#   puts "HI!"
# end

# DRY
# method with one parameter (name)
def greet_student(name)
  puts "Hello #{name}, how are you today? :)"
end

# we ommit the () characters if we don't have arguments!
# greet_person
# greet_person

# we're calling the method greet_student with the ARGUMENT 'Ricardo'
greet_student('Ricardo')
greet_student('Fabi')
greet_student('Hanna')
greet_student('José')


def full_name(first_name, last_name)
  first_name = first_name.capitalize
  last_name = last_name.capitalize

  return "#{first_name} #{last_name}"
end

# full_name is returning nil!
name = full_name('riCarDO', 'oTEro')
puts name


def max(number_1, number_2)
  return 0 if number_1 == number_2

  if number_1 > number_2
    return number_1
  else
    return number_2
  end
end

maximum = max(5, 6) # => 6
puts maximum # => 6

def upcased_name(name)
  5 + 6
  new_name = name.downcase

  # return new_name

  name.upcase
end

upcased = upcased_name('ricardo')
puts upcased

def stupid_method
end

result = puts('Ricardo')
puts result

require 'date'

def tomorrow
  tomorrow_date = Date.today + 1
  return tomorrow_date.strftime("%B %d")
end

puts tomorrow   # => "October 4"

string.rb

puts "Hello world"
puts 'Hello world'

name = 'Ricardo'
age = 37

# Concatenation of strings
# puts 'Hello' + ' ' + name + ' ' + 'how are you?'
puts 'You are' + ' ' + 37.to_s + ' ' + 'years old'

# Interpolation of strings (needs double quotes!)
# puts "Hello #{name} how are you?"
puts "You are #{36 + 1} years old"

vars.rb

# variable names should be lower snake case
user_city = 'Lisbon'

age = 40 # assigning a variable value

age_in_four_years = age + 4

age = age + 4 # re-assignment
age += 4 # sugar syntax to age = age + 4

puts age #=> 44

age = 50 # re-assignment

puts age #=> 50