return

Return Statement

A value created inside a function can't be used outside of it unless you return it.

Consider the following function:

def square(n):
    return n * n
If we wanted to store 5 squared in a variable called x, we would do: x = square(5). x would now equal 25.

Common Mistakes

>>> def square(n):
...     n * n  # calculates then throws away, returns None
...
>>> x = square(5)
>>> print(x)
None
>>> def square(n):
...     print(n * n)  # calculates and prints, then throws away and returns None
...
>>> x = square(5)
25
>>> print(x)
None
Things to note
print() and return do not accomplish the same thing. print() will show the value, and then it will be gone.
• A function will return None if it ends without a return statement.
• When you want to print a value from a function, it's best to return the value and print the function call instead, like print(square(5)).