Methods with return values in Python - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does a method with a return value do?

It performs a task and then sends back a result to the place where it was called.

beginner

How do you define a method that returns a value in Python?

Use the def keyword to define the method, then use return followed by the value you want to send back.

beginner

What happens if a method does not have a return statement?

It returns None by default, which means it sends back no useful value.

beginner

Why is it useful for a method to return a value?

Because it lets you use the result later in your program, like saving it in a variable or printing it.

beginner

Example: What does this method return?<br>

def add(a, b):
    return a + b

It returns the sum of a and b. For example, add(2, 3) returns 5.

What keyword is used to send a value back from a method in Python?

A output

B send

C yield

D return

The return keyword is used to send a value back from a method.

What does a method return if there is no return statement?

A None

B An error

C False

D 0

If no return statement is present, Python methods return None by default.

Which of these is a correct method that returns the square of a number?

A def square(x): x * x

B def square(x): print(x * x)

C def square(x): return x * x

D def square(x): return

Only option A returns the square value properly using return.

Why might you want a method to return a value?

A To reuse the result later

B To stop the program

C To print something

D To create a new method

Returning a value lets you reuse the result later in your program.

What will this code print?<br>

def greet():
    return 'Hello!'
print(greet())

A None

B Hello!

C greet

D Error

The method returns 'Hello!' which is then printed.

Explain how a method with a return value works and why it is useful.

Think about how you get answers back when you ask a question.

Write a simple Python method that takes two numbers and returns their product.

Use <code>def</code> and <code>return a * b</code>.