Accessing and modifying attributes in Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this attribute access code?

Consider this Python class and code. What will be printed?

Python

class Car:
    def __init__(self, brand):
        self.brand = brand

car = Car('Toyota')
print(car.brand)

A Brand

B car.brand

C Toyota

D Error: attribute not found

💡 Hint

Remember, accessing an attribute with dot notation prints its value.

The attribute 'brand' is set to 'Toyota' in the constructor. Accessing car.brand prints 'Toyota'.

❓ Predict Output

intermediate

What happens when modifying an attribute?

What will be the output after modifying the attribute?

Python

class Person:
    def __init__(self, name):
        self.name = name

p = Person('Alice')
p.name = 'Bob'
print(p.name)

A Bob

B None

C Error: cannot modify attribute

D Alice

💡 Hint

You can change attributes by assigning new values.

The attribute 'name' was changed from 'Alice' to 'Bob'. So printing p.name outputs 'Bob'.

❓ Predict Output

advanced

What is the output when accessing a missing attribute?

What happens when you try to access an attribute that does not exist?

Python

class Dog:
    def __init__(self, name):
        self.name = name

d = Dog('Rex')
print(d.age)

A AttributeError

B None

C Rex

D 0

💡 Hint

If an attribute is not set, Python raises an error when accessed.

The attribute 'age' was never set on the object. Accessing it raises AttributeError.

❓ Predict Output

advanced

What is the output after modifying a class attribute?

What will this code print?

Python

class Cat:
    species = 'Felis'

c1 = Cat()
c2 = Cat()
Cat.species = 'Felis catus'
print(c1.species)
print(c2.species)

A Felis\nFelis

B Felis\nFelis catus

C Error: cannot modify class attribute

D Felis catus\nFelis catus

💡 Hint

Class attributes are shared by all instances unless overridden.

Changing Cat.species changes it for all instances. Both print statements output 'Felis catus'.

🧠 Conceptual

expert

Which option causes an error when modifying attributes?

Given this code, which option will cause an error when trying to modify the attribute?

Python

class Immutable:
    __slots__ = ['value']
    def __init__(self, value):
        self.value = value

obj = Immutable(10)

A obj.value = 20

B obj.new_attr = 30

C del obj.value

D print(obj.value)

💡 Hint

Slots restrict adding new attributes not listed.

Because __slots__ limits attributes to 'value', adding 'new_attr' causes AttributeError.