Polymorphism through functions in Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of polymorphic function with different types

What is the output of this code?

Python

def add(a, b):
    return a + b

print(add(5, 10))
print(add('Hello, ', 'world!'))
print(add([1, 2], [3, 4]))

A

15
TypeError
[1, 2, 3, 4]

B

15
Hello, world!
[1, 2, 3, 4]

C

15
Hello, world!
[1, 2][3, 4]

D

TypeError
Hello, world!
[1, 2, 3, 4]

💡 Hint

Think about how the + operator works differently for numbers, strings, and lists.

The add function uses the + operator, which works for integers (adds), strings (concatenates), and lists (concatenates). So all three calls succeed and print the combined results.

❓ Predict Output

intermediate

Function behavior with different input types

What will be printed when running this code?

Python

def describe(x):
    return f'Type: {type(x).__name__}, Value: {x}'

print(describe(42))
print(describe([1, 2, 3]))
print(describe({'a': 1}))

A

Type: int, Value: 42
Type: list, Value: 1, 2, 3
Type: dict, Value: {'a': 1}

B

Type: int, Value: 42
Type: list, Value: [1, 2, 3]
Type: dict, Value: {a: 1}

C

Type: int, Value: 42
Type: list, Value: [1, 2, 3]
Type: dict, Value: {'a': 1}

D

Type: int, Value: 42
Type: list, Value: [1, 2, 3]
TypeError

💡 Hint

Look at how type(x).__name__ returns the type name as a string.

The function returns a string showing the type name and the value. The dictionary prints with quotes around the key because it's a string key.

🔧 Debug

advanced

Identify the error in polymorphic function call

What error does this code raise when executed?

Python

def multiply(x, y):
    return x * y

print(multiply(3, 4))
print(multiply('Hi', 3))
print(multiply([1, 2], '2'))

A TypeError

B SyntaxError

C ValueError

D No error, prints 12, HiHiHi, [1, 2, 1, 2]

💡 Hint

Check the types of arguments in the last call and how multiplication works for lists and strings.

The last call tries to multiply a list by a string, which is not allowed and raises a TypeError. Multiplying a list by an integer repeats the list, but multiplying by a string is invalid.

❓ Predict Output

advanced

Output of polymorphic function with custom classes

What is the output of this code?

Python

class Dog:
    def speak(self):
        return 'Woof'

class Cat:
    def speak(self):
        return 'Meow'

def animal_sound(animal):
    return animal.speak()

print(animal_sound(Dog()))
print(animal_sound(Cat()))

A

Meow
Woof

B AttributeError

C

Woof
Woof

D

Woof
Meow

💡 Hint

Each class has its own speak method. The function calls the method on the passed object.

The function animal_sound calls the speak method on the object passed. Dog returns 'Woof', Cat returns 'Meow'.

🧠 Conceptual

expert

Understanding polymorphism with duck typing

Which option best explains why the following code works without errors?

def operate(x):
    return x.action()

class A:
    def action(self):
        return 'A action'

class B:
    def action(self):
        return 'B action'

print(operate(A()))
print(operate(B()))

A Because both classes have an <code>action</code> method, so <code>operate</code> can call it regardless of the object type.

B Because Python checks the type of the object before calling <code>action</code> and allows only A or B.

C Because <code>operate</code> uses inheritance to call the correct <code>action</code> method.

D Because <code>operate</code> converts objects to strings before calling <code>action</code>.

💡 Hint

Think about how Python decides if an object can do something, not what type it is.

This is duck typing: if an object has the method needed, Python allows calling it without checking the object's class explicitly.