Master the Python Return Statement: Examples & Best Practices

Uncover the power of the Python return statement! Learn how to use it, see practical examples, and improve your coding skills. This comprehensive guide simplifies complex concepts and offers clear, actionable insights for Python developers.

Understanding the Python Return Statement

The return statement in Python is a crucial part of function design. It allows a function to send back a value to the caller, facilitating data manipulation and program flow. It's exclusive to functions and can't be used independently.

What Happens When a Python Function Lacks a Return?

Curious what happens if a function lacks an explicit return statement? Python implicitly returns None. This is useful to understand when debugging or working with functions that primarily perform actions rather than calculations.

Here's an example:

def print_something(s):
    print('Printing::', s)

output = print_something('Hi')
print(f'A function without return statement returns {output}')

Output:

Printing:: Hi
A function without return statement returns None

Decoding the Python Return Statement: Core Examples

Unlock the potential of your functions! The return statement enables you to process information and present results back to the user or other parts of your code.

• Basic Arithmetic: Return sums, differences, products, etc.
• Data Manipulation: Modify and return strings, lists, or dictionaries.
• Conditional Logic: Return different values based on specific conditions.

How to Return a Value with a Python Return

The return keyword is followed by the value or expression you want to send back from the function.

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

output = add(5, 4)
print(f'Output of add(5, 4) function is {output}')

The output is:

Output of add(5, 4) function is 9

Python Return Boolean: Implement Boolean Logic

Use the return statement to return True or False based on your function's logic. This is particularly useful for validation and conditional checks.

def bool_value(x):
    return bool(x)

print(f'Boolean value returned by bool_value(False) is {bool_value(False)}')
print(f'Boolean value returned by bool_value(True) is {bool_value(True)}')
print(f'Boolean value returned by bool_value("Python") is {bool_value("Python")}')

Output:

Boolean value returned by bool_value(False) is False
Boolean value returned by bool_value(True) is True
Boolean value returned by bool_value("Python") is True

Python Return String: Returning Textual Data

Functions can easily return strings, allowing for dynamic text generation and manipulation. Leverage this to create personalized messages, format data, and build flexible applications.

def str_value(s):
    return str(s)

print(f'String value returned by str_value(False) is {str_value(False)}')
print(f'String value returned by str_value(True) is {str_value(True)}')
print(f'String value returned by str_value(10) is {str_value(10)}')

Output:

String value returned by str_value(False) is False
String value returned by str_value(True) is True
String value returned by str_value(10) is 10

Python Return Tuple: Combine and Return Multiple Values

Need to return more than one value? Python's return statement efficiently returns tuples, allowing you to send back multiple pieces of data in a single statement. This is helpful in scenarios where you need to return related, grouped information.

def create_tuple(*args):
    my_list = []
    for arg in args:
        my_list.append(arg * 10)
    return tuple(my_list)

t = create_tuple(1, 2, 3)
print(f'Tuple returned by create_tuple(1,2,3) is {t}')

Output:

Tuple returned by create_tuple(1,2,3) is (10, 20, 30)

Python Function Returning Another Function: Advanced Techniques

Embrace the power of higher-order functions! A Python function can return another function, allowing for flexible and dynamic code. This is related to the concept of "Currying," where functions can be constructed from other functions.

def get_cuboid_volume(h):
    def volume(l, b):
        return l * b * h

    return volume

volume_height_10 = get_cuboid_volume(10)
cuboid_volume = volume_height_10(5, 4)
print(f'Cuboid(5, 4, 10) volume is {cuboid_volume}')

cuboid_volume = volume_height_10(2, 4)
print(f'Cuboid(2, 4, 10) volume is {cuboid_volume}')

Output:

Cuboid(5, 4, 10) volume is 200
Cuboid(2, 4, 10) volume is 80

Python returning function outer function

Explore closure by having functions return functions defined outside their scope.

def outer(x):
    return x * 10

def my_func():
    return outer

output_function = my_func()
print(type(output_function))

output = output_function(5)
print(f'Output is {output}')

Output:

<class 'function'>
Output is 50

Python Return Multiple Values at Once

Returning multiple values from a function in Python is a breeze. You can return tuples, lists, or dictionaries. For super large datasets, the yield statement works best. Use yield to return each value one at a time ensuring efficient memory usage when working with massive data streams.

def multiply_by_five(*args):
    for arg in args:
        yield arg * 5

a = multiply_by_five(4, 5, 6, 8)

print(a)
# showing the values
for i in a:
    print(i)

Output:

<generator object multiply_by_five at 0x000001D27A4BBB30>
20
25
30
40

Key Takeaways of Python Return

The python return statement lets a function return a value and expressions are evaluated before their result is returned. You can return values, functions, and outer functions, etc.