Object-Oriented Programming - Quiz

Complete the code so that creating a User instance automatically prints its readable description.

Complete the expression to access the shared tax_rate defined on the Invoice class.

Complete the code to call a class method that creates a Product from a JSON string.

In OOP, what does encapsulation primarily help you achieve in Python classes?

What is an object in Python OOP terms?

Which of the following is TRUE about the __init__ method?

Which statement about instance attributes is correct?

What happens if you change a class attribute on the class object itself?

Which best describes an instance method in Python?

How is a class method different from an instance method?

When is using a static method most appropriate?

Why is self explicitly included as the first parameter of instance methods?

What does the @property decorator allow you to do?

Which is a common reason to use a setter with @property?

Which built-in function calls the __repr__ method on an object?

What is operator overloading in Python?

Order the steps to define a class with __init__ that stores a user's email and then create an instance.

Drag and drop to reorder, or use the arrows.

Order the steps to add a @property that exposes a full_name attribute built from first_name and last_name.

Drag and drop to reorder, or use the arrows.

What is the output of this code?

1class Counter:
2    total = 0
3
4    def __init__(self):
5        Counter.total += 1
6
7c1 = Counter()
8c2 = Counter()
9print(Counter.total)

What is the output of this code involving __str__?

1class Task:
2    def __init__(self, title):
3        self.title = title
4
5    def __str__(self):
6        return f"Task: {self.title}"
7
8job = Task("Backup")
9print(job)

What does this code print when using a @property for area?

1class Square:
2    def __init__(self, side):
3        self._side = side
4
5    @property
6    def area(self):
7        return self._side * self._side
8
9s = Square(4)
10print(s.area)

What is the output of this operator overloading example?

1class Score:
2    def __init__(self, value):
3        self.value = value
4
5    def __add__(self, other):
6        return Score(self.value + other.value)
7
8    def __repr__(self):
9        return f"Score({self.value})"
10
11s1 = Score(10)
12s2 = Score(5)
13print(s1 + s2)

What is printed by this class and instance attribute combination?

1class Device:
2    status = "offline"
3
4    def __init__(self, status=None):
5        if status is not None:
6            self.status = status
7
8a = Device()
9b = Device("online")
10print(a.status)

Find the bug in this code that tries to use a class method as an alternative constructor.

Click on the line(s) that contain the bug.

class Report:

    def __init__(self, title):

        self.title = title

    def from_markdown(cls, markdown_text):

        title_line = markdown_text.splitlines()[0]

        clean_title = title_line.lstrip('# ').strip()

        return cls(clean_title)

r = Report.from_markdown("# Sales Report")

Find the bug related to getters and setters using @property.

Click on the line(s) that contain the bug.

class Temperature:

    def __init__(self, celsius):

        self._celsius = celsius

    @property

    def celsius(self):

        return self._celsius

    @celsius.setter

    def celsius(self, value):

        if value < -273.15:

            raise ValueError("Too cold")

        celsius = value

t = Temperature(20)

t.celsius = 25

Match each OOP concept to its best description.

Click an item on the left, then click its match on the right. Click a matched item to unmatch.

Match each dunder method to what it customizes.

Click an item on the left, then click its match on the right. Click a matched item to unmatch.

Complete the code so the class uses a @property to expose a read-only full_name built from first and last names.

Complete the code so purchases_count is a class-level counter updated each time a new Order is created via the class method.

Click the line where the class attribute discount is being accessed.

Click on the line to select.

class Invoice:

    discount = 0.1

    def __init__(self, total):

        self.total = total

bill = Invoice(200)

final_amount = bill.total * (1 - Invoice.discount)

print(final_amount)

Click the line where operator overloading for equality is defined.

Click on the line to select.

class Point:

    def __init__(self, x, y):

        self.x = x

        self.y = y

    def __eq__(self, other):

        return self.x == other.x and self.y == other.y

p1 = Point(1, 2)

p2 = Point(1, 2)

print(p1 == p2)