ExamAdept

How can encapsulation be enforced in Python to make a variable 'email' accessible only within its own class?

class User:
    def __init__(self, email, __password):
        self.email = email
        self.__password = __password

A:

Use a getter method for 'email'

B:

Add a single underscore prefix before 'email'

C:

Make 'email' a global variable

D:

Add a double underscore prefix before 'email'

Answer: D

Adding a double underscore prefix before 'email' makes it a private variable, enforcing encapsulation within the class.

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What is the primary purpose of the following Python class?

class Movie:
    def __init__(self, title, __rating):
        self.title = title
        self.__rating = __rating

    def get_rating(self):
        return self.__rating

A:

To create a new instance of the class

B:

To provide controlled access to the 'rating' variable

C:

To define a public variable 'rating'

D:

To allow unrestricted access to the 'rating' variable

Answer: B

The get_rating() method provides controlled and read-only access to the private variable '__rating', demonstrating encapsulation.

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In Python, what is the benefit of using a private variable with a double underscore prefix, such as __total?

class ShoppingCart:
    __total = 0

    def add_item(self, price):
        ShoppingCart.__total += price

A:

It improves code maintainability by hiding implementation details

B:

It allows unrestricted access to __total

C:

It exposes all internal details of __total

D:

It creates a global variable

Answer: A

Encapsulation with a double underscore prefix improves code maintainability by hiding the implementation details of the class attribute __total.

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Consider the following Python code:

class Product:
    def __init__(self, name, __price):
        self.name = name
        self.__price = __price

    def set_discount(self, discount):
        if 0 < discount < 1:
            self.__price *= (1 - discount)

What is the purpose of the set_discount() method?

A:

To retrieve the price of the product

B:

To set a new discount for the product with validation

C:

To create a new instance of the class

D:

To expose all internal details of the class

Answer: B

The set_discount() method allows setting a new discount for the product with validation, demonstrating encapsulation.

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How can encapsulation be enforced in Python to make a variable 'username' accessible only within its own class?

class User:
    def __init__(self, username, __password):
        self.username = username
        self.__password = __password

A:

Use a getter method for 'username'

B:

Add a single underscore prefix before 'username'

C:

Make 'username' a global variable

D:

Add a double underscore prefix before 'username'

Answer: D

Adding a double underscore prefix before 'username' makes it a private variable, enforcing encapsulation within the class.

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Questions for: Encapsulation