Lesson 3.3: Loops – while Loop

Introduction:
The while loop in Python is used to execute a block of code repeatedly as long as a given condition remains true. Unlike the for loop, which iterates over a sequence, the while loop continues until the condition becomes false. This makes it ideal for scenarios where the number of iterations is not predetermined.

1. Syntax of while Loop:

Explanation:

• The loop checks the condition before each iteration.

• If the condition is True, the code block executes.

• Once the condition becomes False, the loop stops.

2. Example – Basic while Loop:

Output:

3. Example – Using while Loop for Input Validation:

4. Infinite Loops and Control:

• A loop with a condition that never becomes False is called an infinite loop.

• Use break to exit an infinite loop manually.

Example – Infinite loop with break:

Practical Tips:

• Ensure the loop condition eventually becomes False to avoid infinite loops.

• Combine while loops with counters or flags for controlled execution.

• Use break and continue to manage loop flow effectively.

Learning Outcome of This Lesson:

• Understand the syntax and working of the while loop

• Use while loops for conditional repetition

• Handle infinite loops safely with break

• Apply loops for real-world scenarios like input validation and repetitive tasks