Build a Grocery List Program: Part 4

4:17 with Jason Seifer

Now that we know how to use arrays and hashes, we're going to build a small program that makes a grocery list for us. In this video, we'll clean up and put the finishing touches on our grocery list program.

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Here is our finished program:

def create_list
  print "What is the list name? "
  name = gets.chomp

  hash = { "name" => name, "items" => Array.new }
  return hash
end

def add_list_item
  print "What is the item called? "
  item_name = gets.chomp

  print "How much? "
  quantity = gets.chomp.to_i

  hash = { "name" => item_name, "quantity" => quantity }
  return hash
end

def print_separator(character="-")
  puts character * 80
end

def print_list(list)
  puts "List: #{list['name']}"
  print_separator()

  list["items"].each do |item|
    puts "\tItem: " + item['name'] + "\t\t\t" +
         "Quantity: " + item['quantity'].to_s
  end

  print_separator()
end

list = create_list()

puts "Great! Add some items to your list."

list['items'].push(add_list_item())
list['items'].push(add_list_item())
list['items'].push(add_list_item())

puts "Here's your list:\n"
print_list(list)

So when we last left off, we had printed out our list. 0:00 And let's go ahead and run this again. 0:05 The item is milk and we only want one thing of milk. 0:08 Okay, let's clean up how this looks a little bit. 0:11 First, since we're sort of duplicating code here, 0:15 by printing out a separator, let's go ahead and make a method out of that. 0:19 And we'll call that method output_separator. 0:24 You know what? Let's call it print_separator. 0:31 And we'll give it an argument of the character that we wanna print. 0:34 And we can go ahead and give this a default value of a dash. 0:39 And all this method is going to do is print that character 80 times. 0:46 Now let's go ahead and 0:55 replace the printing of the separator with the method name. 0:56 Okay. 1:06 Clear my screen here and run this again. 1:09 You know what I can take out the list here. 1:13 I can take out the list inspection since we're printing it on our own now. 1:16 This name is Groceries, and the item that we're adding is milk. 1:21 And 1. 1:26 Okay, now we have a separator. 1:27 But let's go ahead and clean this up even a little bit more. 1:31 So now let's go ahead and indent each line here. 1:35 So we'll print a tab character Inside of this list and 1:38 the item's name and then another plus. 1:43 And let's say we'll do three tab characters here and the quantity. 1:46 Now I want quantity to be all on the same line so 1:51 I'm going to add another plus and take out that put statement. 1:55 And this will create one big string and 2:03 send it in as an argument to the puts method. 2:06 Let me clear my screen here, click in to the console and run this again. 2:09 Okay, this is looking a little bit better. 2:20 We've got our grocery list, and our item of milk, and our quantity of one. 2:22 Let's go ahead and say that we want to add another list item. 2:28 Print my screen and run this again. 2:34 List name is groceries. 2:35 The item is milk, and we only want one. 2:38 Bread, we're gonna say we want two loaves of bread. 2:40 And that looks good. 2:43 We've got a separator in between each of the items. 2:44 But you know what? 2:48 Let's go ahead and print the separator at the end of all the list items instead. 2:49 I think that'll look just a little bit better. 2:53 And now let's go ahead and just add another item to the list. 3:00 And in fact before we print the list, I'm just going to print here's your list. 3:05 And a new line. 3:13 In fact let's go ahead and add another message and say great. 3:16 Add some items to your list. 3:20 Now let me clear my screen here, there's gonna be more output so 3:25 I'm gonna make this a little bit bigger and type ruby.shoppinglist.rb. 3:28 This name is groceries Great. 3:35 Let's add some items to the list. 3:37 Milk, we only need one. 3:40 Bread, two loaves of bread. 3:42 Eggs, let's get three dozen eggs because we're really hungry. 3:45 All right, and here is our grocery list with our three different items and 3:50 the corresponding quantities. 3:55 In this course, we've learned about how arrays and hashes work, and 3:58 have even learned some simple iteration. 4:02 Don't stop now, though. 4:05 Make sure to practice these concepts on your own, and 4:07 practice by building your own programs. 4:10 If you need inspiration, check out the extra credit. 4:12 Happy coding. 4:16

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Build a Grocery List Program: Part 4

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