Python Functions Tutorial

1. What is Function in Python?

Now we will consider what a function in Python and some basic techniques used to create functions is: what are the arguments of the function, what is the return value of the function, what is the body of the function, and how to use the function in the code.

What Is Function?

Challenge: Building functions

2. Positional and Optional Arguments

Python is a fairly flexible language in terms of creating functions. This is especially true in setting function arguments - there are several different types of function arguments, and you can choose any of them depending on the problem you are solving. Let's now take a closer look at them.

Positional Arguments

Challenge: Positional Arguments

Optional Arguments

Challenge: Optional Arguments

3. Arbitrary Arguments

This section of the Python course covers *args and **kwargs, which allow you to handle variable numbers of positional and keyword arguments in functions. `*args` lets you pass any number of positional arguments, making functions more flexible. **kwargs allows you to pass any number of keyword arguments as a dictionary, which facilitates handling complex data structures efficiently.

Arbitrary Arguments

Arbitrary Keyword Arguments

Combination of Positional and Optional Arguments

4. Function Return Value Specification

The return value of a function is the direct result of the execution of the function, which we can use in the program. There are several types of function return values - now we will consider the most commonly used.

Single Return Value

Multiple Return Values

None Return Value

Generator Functions

Challenge: Traffic lights

5. Recursion and Lambda Functions

Now it's time to consider additional topics to help make your functions more flexible and solve more complicated tasks. You will understand recursion, lambda functions, and some basics principles of writing effective and maintainable functions.

Recursion

Challenge: Pyramid

Lambda Functions

Immediately Invoked Lambda Expression

Writing Effective and Maintainable Functions

What Is Function?

In Python, a function is a named block of reusable code that performs a specific task. It is a fundamental concept in programming and plays a crucial role in organizing and structuring code. Functions are like building blocks in LEGO. They allow you to create reusable chunks of code that can be used in different parts of your program.

Firstly, it's convenient because you can call the same block of code multiple times without having to rewrite it. This saves time and reduces the chance of making mistakes;
Secondly, functions help break down complex tasks into smaller, understandable steps. Each function can perform a specific action, making the code more readable and easier to manage.

In simpler terms, functions are like breaking down tasks into smaller pieces that you can use over and over again. This approach makes your program more convenient to write, change, and understand.

Defining a function

Let's to define the most simple function in Python.

Firstly, the def keyword has to be used;
Secondly, we have to specify the function name - a unique identifier that represents the function. It follows variables' naming conventions, such as using lowercase letters and underscores ( this convention is called snake_case);
We have to use (): after the function name - in these brackets, we specify the function's arguments (parameters);
Then, we specify the function body with the indented new line;
After the function body, we can specify the return value of the function using different keywords such as return, assign, or yield;
Finally, we can use functions in code. To do so, we have to call function using its name and specifying its parameters.

Let's look at the example. We will create a simple function to print 'Hello, world!' in the console and use this function in code by calling it.

Code Description

You may have noticed that we used print() function as the body of print_hello(). It is a built-in function that prints the text in the console. It has a string as and arguments - we specify this string in the () brackets.

You may ask why this function has no return value if it prints the message in the console.
In Python, a function can perform a task (in this case, printing a message) without necessarily returning a value. The presence or absence of a return statement in a function depends on whether the function is intended to produce an output (return a value) that can be used in other parts of the program.

The print_hello() function prints a string in the console, but we can't use this string in the program, manipulate it, or use it as an input for other functions. So, the print_hello() function has no return value.

In the next chapter, you will create your first function.

¿Todo estuvo claro?

Sección 1. Capítulo 1

Contenido del Curso

Python Functions Tutorial

1. What is Function in Python?

What Is Function?Challenge: Building functions Arguments Return Value Function Body Built-in Functions

2. Positional and Optional Arguments

Positional Arguments Challenge: Positional Arguments Optional Arguments Challenge: Optional Arguments

3. Arbitrary Arguments

Arbitrary Arguments Arbitrary Keyword Arguments Combination of Positional and Optional Arguments

4. Function Return Value Specification

Single Return Value Multiple Return Values None Return Value Generator Functions Challenge: Traffic lights

5. Recursion and Lambda Functions

Recursion Challenge: Pyramid Lambda Functions Immediately Invoked Lambda Expression Writing Effective and Maintainable Functions

Python Functions Tutorial

What Is Function?

Firstly, it's convenient because you can call the same block of code multiple times without having to rewrite it. This saves time and reduces the chance of making mistakes;
Secondly, functions help break down complex tasks into smaller, understandable steps. Each function can perform a specific action, making the code more readable and easier to manage.

Defining a function

Let's to define the most simple function in Python.

Firstly, the def keyword has to be used;
Secondly, we have to specify the function name - a unique identifier that represents the function. It follows variables' naming conventions, such as using lowercase letters and underscores ( this convention is called snake_case);
We have to use (): after the function name - in these brackets, we specify the function's arguments (parameters);
Then, we specify the function body with the indented new line;
After the function body, we can specify the return value of the function using different keywords such as return, assign, or yield;
Finally, we can use functions in code. To do so, we have to call function using its name and specifying its parameters.

Let's look at the example. We will create a simple function to print 'Hello, world!' in the console and use this function in code by calling it.

Code Description

In the next chapter, you will create your first function.

¿Todo estuvo claro?

Sección 1. Capítulo 1