Purpose of polymorphism in Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a method that can be used by different classes.

Python

class Animal:
    def sound(self):
        [1]

Drag options to blanks, or click blank then click option'

Areturn 5

Bprint('Hello')

Cself.sound()

Dpass

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to call the method inside itself causing recursion.

Returning a value when the method should be empty.

The pass statement is used to define an empty method that can be overridden by subclasses, enabling polymorphism.

2fill in blank

medium

Complete the code to override the method in the subclass.

Python

class Dog(Animal):
    def sound(self):
        [1]('Bark')

Drag options to blanks, or click blank then click option'

Aprint

Breturn

Cpass

Dinput

Attempts:

3 left

💡 Hint

Common Mistakes

Using return instead of print which won't show output.

Leaving the method empty with pass.

The print function outputs the dog's sound, overriding the base class method.

3fill in blank

hard

Fix the error in the code to call the correct method for each animal.

Python

def animal_sound(animal):
    [1].sound()

Drag options to blanks, or click blank then click option'

Aanimal

Banimal.sound()

Canimal()

Danimal.sound

Attempts:

3 left

💡 Hint

Common Mistakes

Adding parentheses after the method name in the blank causing syntax errors.

Using the method name without the object.

The variable animal is the object, so calling animal.sound() is correct. The blank should be the object animal to call its method.

4fill in blank

hard

Fill both blanks to create a list of animals and call their sounds using polymorphism.

Python

animals = [[1], [2]]
for a in animals:
    a.sound()

Drag options to blanks, or click blank then click option'

ADog()

BAnimal()

CCat()

DBird()

Attempts:

3 left

💡 Hint

Common Mistakes

Using the base class Animal() which has no sound implementation.

Using class names without parentheses, which are not instances.

Creating instances of Dog and Cat classes allows calling their overridden sound() methods, demonstrating polymorphism.

5fill in blank

hard

Fill all three blanks to define classes and demonstrate polymorphism with a function.

Python

class [1]:
    def sound(self):
        pass

class [2]([1]):
    def sound(self):
        print('Meow')

def make_sound(animal):
    animal.sound()

make_sound([2]())

Drag options to blanks, or click blank then click option'

AAnimal

BCat

CDog

DBird

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing class names or forgetting to inherit from the base class.

Calling the function with the wrong class instance.

The base class Animal defines the method sound. The subclass Cat overrides it. The function make_sound calls the correct method showing polymorphism.

Practice

1. What is the main purpose of polymorphism in Python programming?

easy

A. To allow one function or method to work in different ways depending on the object

B. To make the program run faster by using multiple processors

C. To store multiple values in a single variable

D. To create a new data type from existing types

Solution

1. Step 1: Understand the meaning of polymorphism

   Polymorphism means one action can behave differently depending on the object it is acting on.

2. Step 2: Match the purpose with the options

   To allow one function or method to work in different ways depending on the object correctly describes this behavior, while others describe unrelated concepts.

3. Final Answer:

   To allow one function or method to work in different ways depending on the object -> Option A

4. Quick Check:

   Polymorphism = One action, many behaviors [OK]

Hint: Polymorphism means same name, different actions [OK]

Common Mistakes:

• Confusing polymorphism with speed optimization
• Thinking polymorphism is about storing multiple values
• Mixing polymorphism with data type creation

2. Which of the following is the correct way to demonstrate polymorphism with methods in Python?

easy

A. Define multiple methods with different names in the same class

B. Define methods with the same name in different classes and call them on their objects

C. Use only one method in one class without overriding

D. Use global variables to change method behavior

Solution

1. Step 1: Recall how polymorphism works with methods

   Polymorphism allows methods with the same name to behave differently in different classes.

2. Step 2: Check which option matches this behavior

   Define methods with the same name in different classes and call them on their objects correctly describes defining same-named methods in different classes and calling them on their objects.

3. Final Answer:

   Define methods with the same name in different classes and call them on their objects -> Option B

4. Quick Check:

   Same method name, different classes = polymorphism [OK]

Hint: Same method name in different classes shows polymorphism [OK]

Common Mistakes:

• Thinking polymorphism means different method names
• Ignoring method overriding in subclasses
• Using global variables to control method behavior

3. What will be the output of the following code?

class Dog:
    def sound(self):
        return "Bark"

class Cat:
    def sound(self):
        return "Meow"

animals = [Dog(), Cat()]
for animal in animals:
    print(animal.sound())

medium

A. Meow
Bark

B. Bark
Bark

C. Error: sound method not found

D. Bark
Meow

Solution

1. Step 1: Understand the classes and their methods

   Dog and Cat classes both have a method named sound that returns different strings.

2. Step 2: Trace the loop calling sound on each object

   The loop calls sound() on Dog instance (returns "Bark") and Cat instance (returns "Meow"), printing each.

3. Final Answer:

   Bark Meow -> Option D

4. Quick Check:

   Different classes, same method name, different outputs [OK]

Hint: Same method name, different classes, different outputs [OK]

Common Mistakes:

• Assuming both calls return the same string
• Expecting a runtime error due to method name
• Mixing the order of outputs

4. Find the error in this code that tries to use polymorphism:

class Bird:
    def fly(self):
        print("Flying")

class Penguin(Bird):
    def fly(self):
        print("Cannot fly")

p = Penguin()
p.fly()

medium

A. No error; code correctly uses polymorphism

B. Penguin class must call super().fly() inside fly

C. Method fly must return a value

D. Penguin class should not override fly method

Solution

1. Step 1: Check method overriding in subclass

   Penguin overrides fly method to print "Cannot fly", which is valid polymorphism.

2. Step 2: Verify code execution

   Creating Penguin object and calling fly prints "Cannot fly" without error.

3. Final Answer:

   No error; code correctly uses polymorphism -> Option A

4. Quick Check:

   Overriding method in subclass is correct polymorphism [OK]

Hint: Overriding method in subclass is allowed [OK]

Common Mistakes:

• Thinking overriding is an error
• Expecting method must return a value
• Believing super() call is mandatory

5. You want to write a function that accepts any object and calls its draw() method, regardless of the object's class. Which concept does this best illustrate?

hard

A. Inheritance

B. Encapsulation

C. Polymorphism

D. Abstraction

Solution

1. Step 1: Understand the function requirement

   The function calls draw() on any object without knowing its class.

2. Step 2: Identify the concept allowing this behavior

   Polymorphism allows different objects to respond to the same method call appropriately.

3. Final Answer:

   Polymorphism -> Option C

4. Quick Check:

   Same method call, different objects = polymorphism [OK]

Hint: Calling same method on any object shows polymorphism [OK]

Common Mistakes:

• Confusing with inheritance which is about class hierarchy
• Mixing with encapsulation which hides data
• Thinking abstraction means calling any method