Book Image

Python Fundamentals

By : Ryan Marvin, Mark Nganga, Amos Omondi
Book Image

Python Fundamentals

By: Ryan Marvin, Mark Nganga, Amos Omondi

Overview of this book

After a brief history of Python and key differences between Python 2 and Python 3, you'll understand how Python has been used in applications such as YouTube and Google App Engine. As you work with the language, you'll learn about control statements, delve into controlling program flow and gradually work on more structured programs via functions. As you settle into the Python ecosystem, you'll learn about data structures and study ways to correctly store and represent information. By working through specific examples, you'll learn how Python implements object-oriented programming (OOP) concepts of abstraction, encapsulation of data, inheritance, and polymorphism. You'll be given an overview of how imports, modules, and packages work in Python, how you can handle errors to prevent apps from crashing, as well as file manipulation. By the end of this book, you'll have built up an impressive portfolio of projects and armed yourself with the skills you need to tackle Python projects in the real world.
Table of Contents (12 chapters)
Python Fundamentals
Preface

User-Defined Functions


As the name suggests, these are functions that are written by the user, to aid them in achieving a specific goal. The main use of functions is to help us organize our programs into logical fragments that work together to solve a specific part of our problem.

The syntax of a Python function looks like this:

def function_name( parameter_one, parameter_two, parameter_n ):
    # Logic goes here
    return

To define a function, we can use the following steps:

  1. Use the def keyword, followed by the function name.

  2. Add parameters (if any) to the function within the parentheses. End the function definition with a full colon.

  3. Write the logic of the function.

  4. Finally, use the return keyword to return the output of the function. This is optional, and if it is not included, the function automatically returns None.

A user-defined function must have a name. You can give it any name that you like, and it is a good practice to make the name as descriptive of the task that the function achieves...