Loop Control & Patterns

Sometimes you need more control over your loops. Python provides statements to alter the flow of a loop: break, continue, and pass.

Control Flow Visualized

The break Statement

break stops the loop immediately and exits it.

The continue Statement

continue skips the rest of the current iteration and moves to the next one.

The pass Statement

pass does nothing. It is a placeholder when a statement is required syntactically but you do not want any command or code to execute.

Loop else Clause

Python has a unique feature: loops can have an else block! The else block executes only if the loop completes normally (i.e., it was NOT stopped by a break).

Common Loop Patterns

1. The Sentinel Value Pattern

This pattern uses a specific value (like "exit" or -1) to signal the end of input.

2. Nested Loops

Practical Example: CLI Menu System

This is a very common pattern for building command-line applications.

Quiz

Key Takeaways

✅ break exits the loop completely
✅ continue skips to the next iteration
✅ pass is a placeholder that does nothing
✅ Loop else runs if the loop finishes without break
✅ while True is common for infinite loops that break on a condition

Module Complete! 🎉

Congratulations! You have completed Module 1: Python Foundations. You now understand:

• Variables & Data Types
• Strings & Numbers
• User Input
• Logic (if/else)
• Loops (for/while)

In the next module, we will start building real structures with Data Structures (Lists, Dictionaries, Sets, Tuples).

Keep coding! 🚀