Your function finally talks back

The problem...

Your functions calculate things. They print things. But the result stays inside the function — and disappears when the function ends.

You can't use it. You can't pass it to another function. You can't store it in a variable.

The function does the work — but keeps the answer to itself.

The idea!

return sends a value back to whoever called the function. The function computes — and hands the result back. You decide what to do with it.

The syntax

def function_name():
    # do something
    return value

The moment Python hits return — the function stops and sends the value back. Everything after return in the same function is ignored.

Your first return

def square(number):
    return number * number

result = square(5)
print(result)    # 25

The function computes 5 * 5 and sends 25 back. You store it in result and use it however you need.

Using the returned value

def square(number):
    return number * number

print(square(3))           # 9 — use directly
x = square(4)              # 16 — store it
print(x + square(2))       # 20 — combine

A returned value behaves like any other value. Print it. Store it. Use it in expressions.

return stops the function

def check(number):
    if number > 0:
        return "positive"
    return "zero or negative"

print(check(5))     # positive
print(check(-3))    # zero or negative

The first return that executes — stops the function. The second one only runs if the first didn't.

Without return — None

def greet(name):
    print(f"Hello, {name}.")

result = greet("Bull")
print(result)    # None

A function without return returns None — Python's way of saying "nothing". It's not an error — it's just empty.

Heads up!

• return stops the function immediately — nothing after it runs
• The returned value can be stored, printed, or used in expressions
• A function without return returns None
• You can have multiple return statements — first one reached wins

The mindset shift

Stop thinking: "My function prints the answer."

Start thinking: "My function computes the answer and hands it back. I decide what to do with it."

What you should understand now

• return sends a value back to the caller
• The returned value can be stored, printed, or passed to another function
• return stops the function — everything after it is ignored
• Without return — the function returns None