Class Inheritance

Quick reference

• 00:04 In this video, I want to talk about class inheritance.
• 00:07 So we've created one class.
• 00:09 It's the employee class, but you can create lots of different classes and
• 00:13 you will.
• 00:13 And a lot of times, you want these classes to interact between themselves to access
• 00:18 themselves and be able to do things from other classes inside of other classes.
• 00:23 And to do that, you use class inherited and that's what we're going to talk about.
• 00:26 So this will be our main class, our employee class, right?
• 00:29 So let's create another class and let's just call it class, let's call it Hired.
• 00:34 And normally, we would go like that just like we did up here.
• 00:37 All right, but in this case,
• 00:39 we want to inherit all the stuff from the employee class.
• 00:43 We want to be able to access all this good stuff inside of our Hired class.
• 00:47 So it's really easy to do that.
• 00:49 We just type in inside of this parenthesis and you can see our program already knows
• 00:54 we're going to ask to do this employee, because it's the only other class.
• 00:58 So we can start to type employee and hit tab and it'll put it right in there.
• 01:02 Now, we could just type a pass in there and
• 01:05 then we can access all of the stuff inside the employee class.
• 01:10 So normally when you create a class, you do this Initialization thing.
• 01:14 But in this case, I don't want to do that,
• 01:16 because I'm going to use all the stuff in this class.
• 01:19 So I could just kind of skip that, but I do want to create,
• 01:24 let's create a Hired class and call it self.
• 01:28 And then let's see, what do we want this to do?
• 01:31 Let's return, just return a string that says, ("You're hired!").
• 01:37 All right, we save this.
• 01:38 Now, we can come down here and let's create an instance of our Hired class.
• 01:43 So we can say, hire_me = and then we call the class name Hired()
• 01:48 which you notice right off the bat, we're getting an error, right?
• 01:53 Well, we're inheriting from the employee class and
• 01:57 the employee class requires a bunch of variables.
• 02:00 A bunch of arguments, a bunch of parameters, four of them, in fact, and
• 02:04 we haven't listed any.
• 02:06 So you have to be sure to create, to pass in the correct number of parameters.
• 02:12 Let's really quickly just go ahead and do this.
• 02:15 I'm just going to go me@me.com.
• 02:17 Salary of 300,000, save this.
• 02:20 Now if we run this, of course, still nothing's going to happen.
• 02:25 We just created an instance, but we haven't done anything with our instance.
• 02:27 So we can go, let's go print hire_me.
• 02:32 Let's do this hired method, .hired.
• 02:35 Forget our parenthesis.
• 02:38 So now if we run this, we get you're hired, right?
• 02:42 So okay, that's just what we would expect to happen.
• 02:45 We created an instance.
• 02:46 Here's our class, we ran the hired method printed this out, okay?
• 02:51 So what?
• 02:52 We've also inherited an employees.
• 02:54 So now inside of this instance, we can access all of these things as well.
• 02:59 So we could pull hire_me.report, you save this and run it.
• 03:04 We get John Elder me@me.com $300,000
• 03:07 even though this is an instance of the Hired class.
• 03:11 And inside the Hired class, there's nothing to do with a report.
• 03:15 There's no mention of anything report related.
• 03:18 But since we inherited everything from the employee class, we can access all
• 03:22 this stuff inside of this hire me instance and then it's just really, really cool.
• 03:27 So that is inheritance, super easy, not much to it.
• 03:30 We just slap in the name of the class we want to inherit from.
• 03:34 And really, the big thing to keep in mind is when you create your instance, you have
• 03:39 to pass in the same number of parameters that the class you're inheriting requires.
• 03:43 In this case, its first name, last name email and pay.
• 03:46 Just keep that in mind or remember to do that and you'll be good to go.
• 03:48 So that is class inheritance and that is the end of our advanced Python section.
• 03:54 And so also the end of the entire course, I hope you enjoyed this.
• 03:57 Python is just a great language.
• 03:59 It's so much fun to use and so easy, and I hope you've sort of got excited.
• 04:04 You just sort of scratched the surface of what you can learn with Python.
• 04:07 There's so much more to learn and I hope you keep learning, and growing.
• 04:10 So I hope you enjoyed the course.
• 04:11 My name is John Elder and thanks for watching.

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