10. What’s Your Function

• 10.1. Introduction
  • 10.1.1. What is a Function?
  • 10.1.2. Function Control Flow
  • 10.1.3. Check Your Understanding
• 10.2. Calling Functions
  • 10.2.1. Making a Function Run
    • 10.2.1.1. Try It!
  • 10.2.2. Why Use Functions?
• 10.3. Defining Our Own Functions
  • 10.3.1. Function Syntax
    • 10.3.1.1. Naming Functions
  • 10.3.2. Function Code
  • 10.3.3. Try It!
  • 10.3.4. Defining vs. Calling
  • 10.3.5. Check Your Understanding
• 10.4. Function Input
  • 10.4.1. Arguments and Parameters
  • 10.4.2. Mismatched Arguments and Parameters
  • 10.4.3. Default Parameter Values
  • 10.4.4. Check Your Understanding
• 10.5. Function Output
  • 10.5.1. Return Statements
    • 10.5.1.1. Returning a Value
    • 10.5.1.2. No return Value
  • 10.5.2. return Stops a Function
  • 10.5.3. Try It!
  • 10.5.4. Check Your Understanding
• 10.6. Boolean Functions
  • 10.6.1. Try It!
• 10.7. A Good Function-Writing Process
  • 10.7.1. Step 1: Design Your Function
  • 10.7.2. Step 2: Create the Basic Structure
  • 10.7.3. Step 3: Write the Body
• 10.8. Parameters and Variables
  • 10.8.1. Function Scope
  • 10.8.2. Variable Shadowing
  • 10.8.3. Check Your Understanding
• 10.9. Functions Calling Other Functions
  • 10.9.1. Palindrome Checker
    • 10.9.1.1. The reverse_string Function
    • 10.9.1.2. The is_palindrome Function
  • 10.9.2. Functions Should Do Exactly One Thing
• 10.10. Why Create Functions?
  • 10.10.1. Functions Reduce Repetition
  • 10.10.2. Functions Make Your Code More Readable
  • 10.10.3. Functions Reduce Complexity
  • 10.10.4. Functions Enable Code Sharing
  • 10.10.5. Functions Save Millions of Lives Every Day
• 10.11. Exercises: Functions
  • 10.11.1. Part A: More Turtles
  • 10.11.2. Part B: Return Values
  • 10.11.3. Bonus Exercises
• 10.12. Project: Functions
  • 10.12.1. Before You Start
  • 10.12.2. Part A: Reverse Characters
  • 10.12.3. Part B: Reverse Digits
  • 10.12.4. Part C: Complete Reversal
  • 10.12.5. Bonus Missions