Python Functions Tutorial – Complete Guide

Python functions can seem like a challenging concept to new coders, but rest assured, they don’t have to be. By the end of this tutorial, you’ll have a solid understanding of what Python functions are, why they’re crucial to the Python programming language, and how to effectively use them in your code.

What Are Python Functions?

Python functions, akin to functions in mathematics or functions of a game character, are reusable blocks of program that carry out a specific task. You can think of them as black box that perform a special power when triggered. To prompt a function, you simply call its name. They’re exceedingly valuable in writing clean and efficient code.

Why Should You Learn About Python Functions?

Let’s imagine you are creating an adventure game. You need to make your character capable of jumping, sprinting, and attacking. Instead of writing out detailed instructions for each action every single time, wouldn’t it be much easier to write them once and then just call them when needed? Well, that’s exactly what Python functions let you achieve!
Learning how to create and use functions in Python equips you to write cleaner, reusable code that is easier to troubleshoot and maintain.

We will delve further into Python functions in the forthcoming sections, demystifying this essential concept with engaging examples and simple game mechanics.

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Creating a Basic Python Function

To create a function in Python, we use the def keyword. This is followed by the function name and parentheses (), where we can include any parameters our function needs. The function’s body, where all magic happens, is indented under def keyword.

def greet_player():
    print("Welcome to the game!")

Above, we’ve created a function called greet_player that prints a welcome message when called. To call this function, we simply use its name followed by parentheses:

greet_player()
# Output: Welcome to the game!

Python Functions with Parameters

Parameters are values we feed into a function. Let’s create a function that takes a player’s name as a parameter:

def greet_player(name):
    print("Welcome to the game, " + name + "!")

Now when we call this function, we need to provide the player’s name:

greet_player("Zenva")
# Output: Welcome to the game, Zenva!

Python Functions with Return Values

Sometimes, we want our function to give us a value back. This is accomplished by using the return statement.

def add_bonus_points(score):
    return score + 500

Above, our function takes the current score, adds 500 bonus points, and returns the new score.

new_score = add_bonus_points(1000)
print(new_score)
# Output: 1500

Multiple Parameters and Returns

Python functions can take multiple parameters and return multiple values. For instance, let’s create a function that calculates both the sum and the average of two scores:

def calculate_scores(score1, score2):
    total = score1 + score2
    average = total / 2
    return total, average

The function can then be called as follows:

total, average = calculate_scores(100, 200)
print("Total: ", total)
print("Average: ", average)
# Output: 
# Total: 300
# Average: 150

Default Parameter Values in Python Functions

In Python, you may set default values to your function parameters. If the caller does not provide a value, the function uses the default value.

def greet_player(name="Player"):
    print("Welcome to the game, " + name + "!")

In this function groom_player, if no parameter is passed, the function will default to “Player”.

greet_player()
# Output: Welcome to the game, Player!

Python’s *args and **kwargs

In Python, *args allows us to pass a varying number of non-keyworded arguments to our function.

def print_scores(*args):
    for score in args:
        print(score)

print_scores(100, 200, 300)
# Output: 
# 100
# 200
# 300

**kwargs lets us pass a varying number of keyworded arguments:

def print_player_scores(**kwargs):
    for player, score in kwargs.items():
        print(player + ": " + str(score))

print_player_scores(Alice=1000, Bob=2000, Charlie=1500)
# Output: 
# Alice: 1000
# Bob: 2000
# Charlie: 1500

Python Lambda Functions

Python also supports the use of small anonymous functions known as lambda functions.

double = lambda x: x * 2
print(double(5))
# Output: 10

In the above example, lambda is followed by the parameter x and the operation x * 2. The function takes a number and returns the number multiplied by two.

Using Python Functions in List Comprehensions

Functions can also be used in list comprehensions to create powerfully succinct blocks of code.

def square(n):
    return n ** 2

numbers = [1, 2, 3, 4, 5]
squares = [square(n) for n in numbers]
print(squares)
# Output: [1, 4, 9, 16, 25]

In the above example, we use our square function in a list comprehension to quickly create a list of squares from our list of numbers.

Where To Go Next with Python?

Dipping your feet into Python functions is only the beginning of your Python learning journey. Up next could be exploring Python classes, modules, file handling, and much more. Each new concept will continue to bolster your prowess in Python programming.

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Our courses at Zenva Academy are designed for both complete beginners and seasoned programmers. You’ll find our learning paths easily adaptable, letting you jump into topics most pertinent to your career aspirations. Our instructors, experienced coders and enthusiastic gamers, foster an engaging, practical learning experience.

Not only will you engage with interactive lessons, tackle coding challenges, and take quizzes to reinforce your learning, but you’ll also create Python projects that can automatically bolster your coding portfolio. Earn completion certificates as badges of your growing Python skills accessible 24/7 and can be accessed on any device.

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Never stop learning, never stop coding. With Zenva, every new Python function, method, or concept you learn is another stepping stone on your exciting coding journey. We can’t wait to see where your Python skills will take you!

Conclusion

So, Python learners, are you ready to take the leap from dabbling in basic Python functions to confidently juggling classes, modules, algorithms, and even game development using Python? With our Python Mini-Degree, you’ll gain an all-encompassing, career-boosting understanding of Python and its diverse applications.

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