Functions & return · About 10 minutes

Invent your own superpower

The big little idea

A function is a reusable recipe. Define it with def, give it a name, and call it whenever you need that recipe. Parameters let the recipe work with different ingredients.

def double(number):
    return number * 2

print(double(6))

return sends a value back to the place where the function was called. It is different from print(): return gives the result to your code, while print() displays it to the person running the program.

Predict, then try: read the example from top to bottom. What do you think it will print? Copy it into the editor below to test your prediction.

Your turn, code explorer.

Write a triple function that returns a number multiplied by 3. Calling triple(7) should print 21.

Output goal

Your code

def triple(number):
    return number

print(triple(7))

Edit the code. Then run it. Ctrl / ⌘ + Enter also works.

OutputYOUR IDEAS, ALIVE

Your program’s output will appear here.

Ready when you are. ✦

The first run loads Python. This can take a moment.

Program input For programs that use input()

Answers, one per line, in the order your program asks

Add answers before you run. Each input() reads the next line. Use made-up names and details.

Real Python, powered by Pyodide. Standard-library programs work here; desktop windows, turtle graphics, and package installation are not supported by this editor. Programs stop after 10 seconds of execution.

A little hint, please

Change the return line to return number * 3. Keep it indented.

Show one possible solution

There can be more than one way. Read this version, then try writing it yourself.

def triple(number):
    return number * 3

print(triple(7))

Pack this idea for later: Functions help you organize a program and reuse an idea.