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Chapter 20: Control Flow and Loops

Programs need to make decisions and repeat actions. Should we process this user's order or reject it? Should we retry a failed network request? Should we validate every item in a list? Control flow structures answer these questions by letting your code respond to different conditions and automate repetitive tasks.

Control flow structures are the foundation of programming logic—they let your code respond to different conditions and automate repetitive tasks. You'll master conditional statements, pattern matching, loops, and control mechanisms that transform simple scripts into intelligent programs.

🎯 Before You Begin​

What You'll Learn​

By the end of this chapter, you will be able to:

  • Make decisions in code using if, elif, and else statements
  • Use pattern matching with Python's modern match-case syntax
  • Automate repetition using for and while loops
  • Control loop behavior with break, continue, and loop-else patterns
  • Combine decisions and loops to solve complex problems
  • Describe your intent clearly so AI can help you write correct control flow logic
  • Validate your logic by testing edge cases and understanding execution flow