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Start creating object structures using Python's class keyword.
-
class- the keyword you use in Python to create an object - Instantiation - creating an object from a class by calling the class like a function
- Instance - the object that was instantiated (created) Ex:
Car() -
isinstance(object, type, or class)- check if an object is an instance of the given type or class
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You know object-oriented
programming is a way to structure
0:00
your code into groups of properties and
behaviors.
0:04
But what does that look
like in Python code?
0:08
Let's use our car example to build out an
object, or class as it's called in Python.
0:13
Use the workspaces attached to
this video to follow along.
0:20
You can also download the file and
use an IDE of your choice if you'd rather.
0:24
In Python objects are created
using the class keyword and
0:33
the name of your class
with a colon like this.
0:36
We're naming our class, Car.
0:44
Always remembered to try and
name things descriptively when coding.
0:46
Classes, functions, variables, etcetera.
0:50
Inside of our class,
we're just going to add, pass.
0:54
So Python knows to keep moving
instead of giving us an error.
0:59
If we don't have pass inside of our class,
1:04
when we run the file,
Python gives us a syntax error.
1:06
Unexpected end of file while parsing.
1:13
You may also see a class
written like this,
1:20
with a set of parentheses
after the name of the class.
1:23
Classes can take arguments.
1:27
We won't get into this idea called
inheritance in this course.
1:30
But I wanted to make sure you know
that a class can be written with or
1:35
without the parentheses, in case you
come across it out there in the wild.
1:39
Classes are kind of like a factory.
1:44
They hold all of the information
about an object like a blueprint.
1:47
When you use your class to
create an object in Python,
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it's called instantiation.
1:56
And the object itself
is called an instance.
1:59
Let's create one now.
2:03
You create an instance of class
car like you would a function.
2:05
Use the name of the class
followed by parentheses.
2:08
You can also save
the instance to a variable.
2:12
Now I know our class
doesn't have a lot to it.
2:18
Well, it has nothing to it right now.
2:21
But we can still check to
see if we made an object.
2:24
Let's try printing out our instance.
2:27
And let's also check its type.
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print(my_car), print(type(my_car).
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The first message shows we created
an instance of our car class.
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It's an object at this location in memory.
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The second message tells us
our objects type is class car.
3:01
Cool.
3:06
There's also a way to check if
something is an instance of a class.
3:08
You can use a built-in
function called isinstance,
3:13
and pass in the object you want to check.
3:17
And the class you want
to check it against.
3:20
It returns a Boolean value
telling us whether or
3:23
not the instance is
an instance of the given class.
3:26
Print(isinstance(my-car and
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Car with a capital C for the class.
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Run the file.
3:46
Our example here is pretty obvious but
it might come in handy later on.
3:48
I've just thrown a lot of new terms and
information at you.
3:54
So let me recap.
3:58
In Python, you create a blueprint for
4:00
your object using the class keyword,
the name of your class, and a colon.
4:03
When you create an object using your
class, it's called instantiation.
4:09
The object you've created
is called an instance.
4:14
You can use print, type, and isinstance to
see if you've correctly made an object.
4:19
Try creating a few empty classes of
your own, then create instances of them.
4:27
Check your work using print,
type, and isinstance.
4:33
Keep up the hard work Pythonistas.
4:37
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