Lesson 4.2: Return Statement and Scope of Variables

Introduction:
In Python, understanding the return statement and variable scope is crucial for writing organized and bug-free code. The return statement allows functions to send results back to the caller, while variable scope determines where variables can be accessed within a program.

1. The Return Statement:

• The return statement sends a value from a function back to the caller.

• A function without return returns None by default.

Example – Using return:

Output:

Key Points:

• You can return multiple values as a tuple.

2. Variable Scope in Python:

• Scope determines the visibility and lifetime of a variable.

Types of Scope:

1. Local Variables:

   • Defined inside a function

   • Accessible only within that function

2. Global Variables:

   • Defined outside any function

   • Accessible anywhere in the program

3. Global Keyword:

   • Allows modifying global variables inside a function

Practical Tips:

• Prefer using local variables to avoid unintended side-effects

• Use the return statement to pass results instead of relying on global variables

• Keep functions self-contained and modular

Learning Outcome of This Lesson:

• Understand the purpose and use of the return statement

• Return single or multiple values from functions

• Distinguish between local and global variables

• Apply variable scope rules to write cleaner, bug-free code

• Modify global variables safely using the global keyword