How to Return List in Python

In this comprehensive guide, we will delve into the world of Python lists, exploring how to return a list from a function. Whether you’re a beginner or an experienced developer, this tutorial is desig …

Updated May 20, 2023

Definition of Returning List in Python

In Python programming, returning a list means sending back a collection of values from a function that can be used by the caller. This is achieved through the use of the return statement within a function. The returned list can then be assigned to a variable or used in further calculations.

Step-by-Step Explanation: Creating and Returning Lists

Here’s a step-by-step guide on how to create and return lists:

Step 1: Defining a Function

def get_numbers():
    pass # empty function for now

This defines an empty function named get_numbers.

Step 2: Populating the List

Inside your function, you would create or populate a list with desired values:

numbers = [1, 2, 3, 4, 5]

Here, we’re creating a simple list of integers from 1 to 5.

Step 3: Returning the List

To return this list, we use the return statement like so:

def get_numbers():
    numbers = [1, 2, 3, 4, 5]
    return numbers # <--- This is where the magic happens!

This indicates to Python that when this function is called and executed, it should send back (or “return”) the list numbers.

Step 4: Calling the Function

To see the returned list in action, you would call the function from another part of your code:

my_list = get_numbers()
print(my_list)

When run, this will print out [1, 2, 3, 4, 5], showing that our function successfully returned a list.

Code Explanation

def get_numbers():: Defines the function get_numbers.
numbers = [1, 2, 3, 4, 5]: Creates a list of integers and assigns it to the variable numbers.
return numbers: Tells Python to send back (or return) the numbers list when this function is called.
my_list = get_numbers(): Calls the get_numbers function, storing its returned value in the my_list variable.
print(my_list): Prints out the contents of my_list, which was populated by calling get_numbers.

Real-world Example

In a real-world scenario, you might have a list representing names and ages of people:

people = [
    {"name": "John", "age": 25},
    {"name": "Mary", "age": 31},
    {"name": "Bob", "age": 42}
]

def get_people_info():
    return people

info_list = get_people_info()
for person in info_list:
    print(f"{person['name']} is {person['age']} years old.")

This example showcases how returning a list can be used to share complex data structures between parts of your code.

Conclusion

Returning lists in Python is a powerful technique for sharing collections of values from one part of your code to another. By mastering this concept, you’ll find yourself creating and manipulating lists with ease, enhancing the efficiency and clarity of your Python programs.