Struct

4:15 with Jason Seifer

In Ruby, a Struct is a shortcut to creating a class with accessor methods. You could create these yourself using simple classes but structs save you a bit of time.

Teacher's Notes
Video Transcript
Downloads

Code Samples

Here is our struct:

Customer = Struct.new(:name, :email) do
  def name_with_email
    "#{name} <#{email}>"
  end
end

We can then create a new instance and iterate through the attributes:

customer = Customer.new("Jason", "jason@teamtreehouse.com")
customer.each_pair do |name, value|
  puts "#{name} - #{value}"
end

Now we're going to take a look at structs. 0:00 In Ruby, a struct is a shortcut to creating a class with accessor methods. 0:03 You could create these yourself using simple classes, but 0:10 structs save you a bit of time. 0:13 Let's see how structs work now using workspaces. 0:16 So here is the struct documentation. 0:20 Now if you look at the notes below the video 0:23 you will be able to see the struct documentation in there. 0:26 So let's go ahead and see what a struct is. 0:29 If we scroll down here we can see that we can create a struct 0:32 by calling new, passing in a string for 0:37 the class that we want, and then the attributes that are present. 0:40 We can also use the class name that we want with and 0:46 equals sign and then Struct.new with the attributes. 0:49 Let's go ahead and see how that works. 0:55 So over here, I've launched a new Ruby workspace and 0:57 right now, I have a class called customer, the customer has two attributes. 1:00 A name and an email. 1:05 Now this is something we've seen before. 1:07 This is just a standard class, and then we instantiate a new customer and 1:09 inspect it, and I'm just gonna show you how this works, and 1:14 here we see this customer has been instantiated. 1:19 So, if we wanted to do this as a struct we could take all this out here. 1:23 And just say customer is a new struct with a name and email. 1:37 Now I'm gonna clear the screen down here and 1:44 run this again, and if we look, we see that we have the exact same thing. 1:48 The only difference is the class has changed from customer to a struct, 1:53 and it is still a class, just a struct customer class. 1:58 Now if we wanted to, we could add in a block here. 2:05 Then anything inside this block would be 2:10 evaluated in the context of this struct class. 2:13 So we can write instance methods here as well. 2:17 As an example, we could say name with email, 2:21 and then evaluate the name, and the email address. 2:27 And then I'm just gonna print that out to the screen, customer.name_with_email. 2:33 Now if I were to run this again, we can see that the name and 2:41 email address are printed out, just gonna clear that. 2:45 Structs are neat because each of the attributes 2:50 will be passed as a block to the each method. 2:53 So I'm gonna clear my screen, run this again and 3:07 we can see the attribute was printed to the screen the value of it. 3:10 If we look back at the struct documentation, 3:15 and scroll down here we can see there's also each pair. 3:19 That we can pass in so we get the attribute name and the value. 3:24 So let's go ahead and change that. 3:27 Name and value, and we'll just say, name and value. 3:35 So I'm gonna save that, run it again, and 3:41 we can see the name and value are printed out for each attribute. 3:46 Now when you're creating a struct if you start having a lot of methods in here, 3:50 it might be time to change and create a real class out of it. 3:56 Structs are mainly meant to be convenience classes when creating 4:01 something with just a couple of attributes that you want to access in this format. 4:06 Try creating some struct on your own now using workspaces. 4:11

You need to sign up for Treehouse in order to download course files.

Ruby Core and Standard Library

Struct

Links

Code Samples