how do you define a function in python? how would you return a value from a function?

February 18, 2026

You define a function in Python with the def keyword, and you return a value using the return statement.

Here’s the quick scoop in a Q&A style.

What is a function in Python?

A function is a reusable block of code that you can “call” whenever you need it, instead of repeating the same code over and over.

It can take input values (called parameters or arguments).

It can do some work inside.
It can optionally send a result back using return.

How do you define a function?

Basic syntax:

python

def function_name(parameters):
    # function body
    # do something here
    return some_value  # optional

Key points.

Use def to start the definition.
Then the function name (must be a valid identifier, like add_numbers or greet).

Parentheses () contain parameters (or are empty if none).
A colon : ends the line.
The body is indented under the definition.
You can use return inside to send a result back.

Example – function with no return (it just prints):

python

def say_hello():
    print("Hello!")

Calling it:

python

say_hello()  # prints: Hello!

This function doesn’t return a value; it only performs an action (printing).

How do you return a value from a function?

You use the return statement followed by the value (or expression) you want to send back.

Example – simple add function:

python

def add(x, y):
    result = x + y
    return result

Using it:

python

answer = add(5, 4)
print(answer)  # 9

Important behavior.

return sends a value , not a variable itself.
When return runs, the function stops immediately (no further lines in that function are executed).

If you don’t write return at all, Python automatically returns None.

Can a function return multiple values?

Yes, commonly by returning a single container like a tuple, list, or dictionary.

Example – returning a tuple:

python

def get_point():
    x = 3
    y = 4
    return x, y  # actually returns a tuple (3, 4)

Using it with unpacking:

python

px, py = get_point()
print(px, py)  # 3 4

Under the hood, return x, y returns one object (the tuple (x, y)), and you unpack it into two variables.

Returning vs printing

A really common beginner question is whether you should print or return.

print() shows something on the screen for the user.
return sends a value back to the caller so your code can use it later (store it, compute with it, pass it to another function, etc.).

Example – printing only:

python

def add_and_print(x, y):
    print(x + y)

result = add_and_print(3, 4)
print("result is:", result)

Output:

text

7
result is: None

Because the function doesn’t return anything, result becomes None.

Example – returning :

python

def add_and_return(x, y):
    return x + y

result = add_and_return(3, 4)
print("result is:", result)  # result is: 7

Here, result actually holds the value 7, which you can reuse in more calculations.

Mini step‑by‑step example

Imagine you’re writing a small program to calculate the area of a rectangle.

Define the function:

python

def rectangle_area(width, height):
    area = width * height
    return area

Call it and store the returned value:

python

a = rectangle_area(5, 10)
print(a)  # 50

Use the returned value again:

python

double_area = a * 2
print(double_area)  # 100

This shows how return gives you a reusable value, instead of just printing something once.

Tiny FAQ

Do I have to usereturn?
No. A function can just perform actions (like printing or modifying a file) and not return anything. In that case, it implicitly returns None.

Can I have multiplereturn statements?
Yes, but only one will run per call, because once a return executes, the function stops. Developers often use this to handle early exits or different branches.

Can I usereturn outside of a function?
No, that causes an error; return is only valid inside a function.

Quick TL;DR

Define a function with def name(parameters): and an indented body.

Use return inside the function to send a value back to where it was called.

return stops the function immediately and returns a value (or None if omitted).

Information gathered from public forums or data available on the internet and portrayed here.