Create a Child Class (Solution)
00:00
To create a child class from a class, what you need to do is, again, use the class
keyword, then type in the name of your class, so GoldenRetriever
, and then you can open up parentheses here and then put in the parent class and then close the parentheses and finish it off with a colon as usual. In the next line, I’m going to for now put a pass
keyword just to satisfy Python’s need for some indented code after a colon, but I’m not going to implement any functionality in the child class so far.
00:37 That’s really all you need to do to create a child class. After the name of the child class, you have to put the name of the parent class in parentheses. That’s it.
00:47
And now GoldenRetriever
has all the functionality that the Dog
class has as well as all the attributes. So we can try that out. I’m going to run the code
00:58
and jump over in the interactive shell. And now I’m going to make a GoldenRetriever
. We call him, buddy
. GoldenRetriever()
and again, it needs a name and an age. We called him buddy
, so let’s stick with that. It’s an old dog, 12
years old. No complaints.
01:26
So now I have an instance of GoldenRetriever
. Here you can also see that if I print()
the representation of Buddy
, then it says in the main namespace, I have a GoldenRetriever
object at a certain memory location.
01:40
Great, and what can buddy
do? buddy
can speak()
.
01:49
I can print(buddy)
. So the .__str__()
also gets taken over from the parent class, So the same format. you can also access the class attribute through the instance—what’s it called?—.species
.
02:07
And you can see that it’s still a Dog
. All right, so with this short two lines of code, you created a child class that inherits from the Dog
parent class.
02:19 Let’s see what else we can do to review everything that you’ve learned in the associated course.
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