Super function usage in Python - Step-by-Step Execution

Concept Flow - Super function usage

Define Base Class

↓

Define Derived Class

↓

Call Derived Method

↓

Inside Derived: call super()

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Execute Base Class Method

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Return to Derived Method

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Finish Derived Method

Shows how a derived class method calls its base class method using super(), then continues execution.

Execution Sample

Python

class A:
    def greet(self):
        print('Hello from A')

class B(A):
    def greet(self):
        super().greet()
        print('Hello from B')

b = B()
b.greet()

A derived class B calls the greet method of its base class A using super(), then prints its own message.

Execution Table

Step	Action	Evaluation	Output
1	Create instance b of class B	b is B instance
2	Call b.greet()	Calls B.greet()
3	Inside B.greet(), call super().greet()	Calls A.greet()
4	Execute A.greet()	Print 'Hello from A'	Hello from A
5	Return to B.greet()	Print 'Hello from B'	Hello from B
6	Finish B.greet()	Method ends

💡 Method B.greet() finishes after calling base method and printing its own message

Variable Tracker

Variable	Start	After 1	After 2	Final
b	undefined	B instance created	B instance	B instance

Key Moments - 2 Insights

Why do we use super().greet() inside the derived class method?

Using super().greet() calls the base class method so we can reuse its code before adding more behavior, as shown in execution_table step 3 and 4.

Does the base class method replace the derived class method?

No, the derived method calls the base method using super(), then continues its own code, as seen in steps 4 and 5.

Visual Quiz - 3 Questions

Look at the execution table, what is printed at step 4?

A 'Hello from A'

B 'Hello from B'

C Nothing

D Error

💡 Hint

Check the Output column at step 4 in the execution_table

At which step does the derived class method print its own message?

A Step 4

B Step 5

C Step 3

D Step 6

💡 Hint

Look at the Action and Output columns in execution_table for when 'Hello from B' is printed

If we remove super().greet() call, what changes in the output?

A Only 'Hello from A' is printed

B Both messages are printed as before

C Only 'Hello from B' is printed

D No output is printed

💡 Hint

Consider that super().greet() triggers 'Hello from A' print in step 4

Concept Snapshot

Use super() in a derived class method to call the base class method.
Syntax: super().method_name()
This lets you reuse base code and add new behavior.
The base method runs first, then derived code continues.
Without super(), base method is not called.

Full Transcript

This visual execution shows how the super() function works in Python. We have a base class A with a greet method that prints a message. The derived class B overrides greet but calls super().greet() to run the base method first. Then B prints its own message. The execution table traces each step: creating an instance, calling B.greet(), calling A.greet() via super(), printing messages, and finishing. The variable tracker shows the instance b stays the same. Key moments clarify why super() is used and that the base method does not replace the derived one. The quiz tests understanding of output at each step and effects of removing super(). The snapshot summarizes the usage and behavior of super() in simple terms.