Programming basics — batch 224

methods.rb

# methods.rb

# method names should be snake_cased
# no arguments
def random_method
  return 10
end

# puts random_method

# Method with two parameters
def full_name(first_name, last_name)
  first = first_name.capitalize
  last = last_name.capitalize
  # NEVER USE PUTS INSIDE YOUR METHODS!
  # puts "#{first} #{last}"
  return "#{first} #{last}"
end

# We are calling full_name with 2 arguments
his_name = full_name('joão', 'costa')
my_name = full_name('ricardo', 'otero')

puts "His name is #{his_name}"
puts "My name is #{my_name}"

strings.rb

# strings.rb

# 2019 - 1999

# String concatenation
puts "My age is" + " " + (2019 - 1999).to_s + " " + "years old"

# String interpolation [preferred]
# It will call .to_s implicitly
puts "My age is #{2019 - 1999} years old"

# puts 'My age is #{2019 - 1999} years old' # this won't work!

variables.rb

# variables.rb

# Assigning a new value to the var. age
age = 2019 - 1999

puts "My age is #{age} years old"

# Reassignment
# snake_case!
new_age = age + 1

puts "My age was #{age} but now is #{new_age} years old"

first_name = 'ricardo'
last_name = 'otero'

first_name.capitalize # won't change the variable

# Destructive method
first_name.capitalize! # will change the variable

puts "My name is #{first_name} #{last_name.capitalize}"

puts first_name # it will be capitalized!