Example Solution for Students -- Dev Bootcamp Guided Pairing 2.2: Create an Electronic Grocery List

advanced_commadline_grocery_list.rb

# Advanced solution w/ commandline input
#
def new_list
  {}
end

def add(item, quantity, list)
  return list[item] = quantity unless list[item]
  puts "#{item.upcase} is already on your list! Use command `update` to change the quantity."
end

def remove(item, list)
  list.delete(item) { |i| puts "Whoops! #{i.upcase} wasn't on your list!" }
end

def update(item, quantity, list)
  return list[item] = quantity if list[item]
  puts "Whoops! #{item.upcase} wasn't on your list! Use `add` to add your item."
end

def print(list)
  list.each { |item, quantity| puts "#{item.upcase} - #{quantity}" }
end

def help
  puts <<-helpdocs

    The following commands are available. Separate input with a single space, e.g.:
      add 10 chips

    add <number> <item>           add an item to your list
    remove <item>                 remove an item from your list
    update <item> <quantity>      update an item's quantity on your list
    help                          show this list of commands
    quit                          exit the program
  helpdocs
end

def run
  puts "Hello! Lets get ready to shop!\n"\
       "Type 'help' to see a list of available commands."
  list = new_list
  input = ""

  until input[0] == "quit"
    puts "\nWhat would you like to do?\n"
    input = gets.chomp.split(" ")

    case input[0]
    when 'add' then add(input[2], input[1], list)
    when 'remove' then remove(input[1], list)
    when 'update' then update(input[1], input[2], list)
    when 'help' then help; next
    else puts "Try again..."
    end

    puts "\n*******************"
    puts "This is your list:"
    print(list)
  end
end

run

basic_grocery_list.rb

# Requirements
#
# Create a new list
# Add an item with a quantity to the list
# Remove an item from the list
# Update quantities for items in your list
# Print the list (Consider how to make it look nice!)

# Initial solution
#
def new_list(items)
  list = {}
  items.split.each { |item| add(item, "1", list) }
  print(list)
end

def add(item, quantity, list)
  if list[item]
    puts "#{item.upcase} is already on your list! Use `update` to change the quantity."
  else
    list[item] = quantity
  end
  print(list)
end

def remove(item, list)
  if list[item]
    list.delete(item)
  else
    puts "Whoops! #{item.upcase} wasn't on your list!"
  end
  print(list)
end

def update(item, quantity, list)
  if list[item]
    list[item] = quantity
  else
    puts "Whoops! #{item.upcase} wasn't on your list! Use `add` to add your item."
  end
  print(list)
end

def print(list)
  puts '-- LIST --'
  list.each do |item, quantity|
    puts "#{item.upcase} - #{quantity}"
  end
end

my_list = new_list("Milk Butter Eggs")

# Tests
puts my_list == {"Milk" => "1", "Butter" => "1", "Eggs" => "1"}
puts add("Carrots", "10", my_list) == {"Milk" => "1", "Butter" => "1", "Eggs" => "1", "Carrots" => "10"}
puts add("Carrots", "20", my_list) == {"Milk" => "1", "Butter" => "1", "Eggs" => "1", "Carrots" => "10"}
puts add("Apples", "15", my_list) == {"Milk" => "1", "Butter" => "1", "Eggs" => "1", "Carrots" => "10", "Apples" => "15"}
puts remove("Oranges", my_list) == {"Milk" => "1", "Butter" => "1", "Eggs" => "1", "Carrots" => "10", "Apples" => "15"}
puts remove("Apples", my_list) == {"Milk" => "1", "Butter" => "1", "Eggs" => "1", "Carrots" => "10"}
puts update("Carrots", "20", my_list) == {"Milk" => "1", "Butter" => "1", "Eggs" => "1", "Carrots" => "20"}
puts update("Oranges", "20", my_list) == {"Milk" => "1", "Butter" => "1", "Eggs" => "1", "Carrots" => "20"}