Ruby 04-Flow-Control Lecture

01-recap.rb

# Data Types / Built-in Objects
"Hello" # String
'Hello' # String

4 # Integer
4.3 # Float

false # Boolean

p [3, "Hello", 3.4, true] # Array

#   method
first_name = "rui" # variable
last_name = "freitas"

# concatenation
puts first_name.capitalize + " " + last_name.capitalize


# interpolation
puts "#{first_name.capitalize} #{last_name.capitalize}"


# Methods

def full_name(first_name, last_name)
  return "Hello, Beatrix!" if first_name == 'Beatrix'
  "#{first_name.capitalize} #{last_name.capitalize}"
end

p full_name('Beatrix', 'Kiddo')
p full_name('Rui', 'Freitas')

02-flow.rb

# puts "How old are you?"
# print "> "

# age = gets.chomp.to_i

# IF structure
# if age >= 18
#   puts "You can vote!"
# end

# Inline if (same as above)
# puts "You can vote!" if age >= 18

# puts "You can vote!" unless age < 18

# IF/ELSE structure
if age >= 18
  puts "You can vote!"
else
  puts "Go home! You're a kiddo!"
end

03-coin_toss.rb

puts "heads or tails?"
print "> "

# use input(string)
guess = gets.chomp

# randomized result(string)
coin = ['heads', 'tails'].sample

# if guess == coin
#   puts "Winner!"
# else
#   puts "Loser!"
# end

# ternary operator

result = guess == coin ? "Winner" : "Loser"

puts "#{result}, that was #{coin}!"

04-greeting.rb

hour = Time.now.hour

if hour < 12
  puts "Good morning!"
elsif hour >= 20
  puts "Good night!"
elsif hour >= 12 && hour != 13
  puts "Good afternoon!"
else
  puts "Enjoy your lunch!"
end

05-interface.rb

puts "Which action? [read | write | list | dance | exit]"
print "> "

choice = gets.chomp.downcase

case choice
when "read"
  puts "You are in read mode"
when "write"
  puts "You are in write mode"
when "list"
  puts "You are in list mode"
when "dance"
  puts "Dancingggg..."
when "exit"
  puts "Goodbye"
else
  puts "Incorrect input"
  puts "Plese try again"
end

06-bootcamp.rb

# Bootcamp is open from 9 to 19
# But closes for lunch (13 to 14)

hour = Time.now.hour

#  morning period
def is_morning?(hour)
  (hour >= 9 && hour < 13)
end

#  afternoon period
def is_afternoon?(hour)
  (hour >= 14 && hour < 19)
end

condition = is_morning?(hour) || is_afternoon?(hour)

if condition
  puts "We're open! Welcome!"
else
  puts "Sorry, we're closed. Come back later!"
end

# Using ternary operator
# condition ? do something : do something else

07-looping.rb

price_to_find = rand(1..5) # integer
choice = nil

# p choice != price_to_find
# while choice != price_to_find
#   puts "Guess the price?"
#   print "> "
#   # always give a chance to update condition
#   choice = gets.chomp.to_i # convert to integer
# end

# if / unless -> test condition, run once
# while / until -> test condition, loop
until choice == price_to_find
  puts "Guess the price?"
  print "> "
  # always give a chance to update condition
  choice = gets.chomp.to_i # convert to integer
end

puts "You won!! The price is #{price_to_find}"


for i in (1..10)
  puts i
end

for i in ["a", "b", "c"]
  puts i
end

08-array.rb

# ARRAYS

# CRUD

# Create

arr = Array.new
# arr = []
p arr.class
arr2 = [4, 5, 6]
p arr2

# Reading
#          0         1      2         3
names = ["tango", "cash", "utah", "bodhi"]
p names

puts names[2]

# Update
names[2] = "johnny"
p names

names.last.capitalize!
p names

# Delete
# delete by index
names.delete_at(1)
p names

# delete by value
numbers = [4, 5, 2, 67, 2, 5, 2, 355]
p numbers
numbers.delete(5)
p numbers

# Array methods
# gets rid of duplications
p numbers.uniq

p names.sort!
p names.reverse