Day 13 of 30Logic & Data Structures
🧩Functions
🎯 Today's objective
Package reusable logic into named functions.
📖 Key concepts
- def name(params): defines a function
- return sends a value back
- Functions avoid repetition (DRY)
- Call with name(args)
💻 Try this code
def greet(name):
return f"Hello, {name}!"
def area(w, h):
return w * h
print(greet("AI"))
print("Area:", area(4, 5))👥 Learn it your way
🧒 Young Explorers
A function is a magic spell you name once and reuse forever.
Your task
Write is_even(n) that returns True/False, and use it on 5 numbers.
💼 Professionals
Keep functions small and single-purpose; name them as verbs; return rather than print.
Your task
Write celsius_to_f(c) and f_to_celsius(f); verify they round-trip a value.
🤖 AI connection
A trained model is basically a function: give it input (features), it returns output (a prediction). model.predict(x) is just a function call.
✅ Quick check
What does return do?
Sends a value back to whoever called the function.
Why use functions?
Reuse, clarity, and avoiding repeated code (DRY).