Book Image

Python Fundamentals

By : Ryan Marvin, Mark Ng’ang’a, Amos Omondi
Book Image

Python Fundamentals

By: Ryan Marvin, Mark Ng’ang’a, Amos Omondi

Overview of this book

<p>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.</p> <p>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.</p> <p>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.</p>
Table of Contents (12 chapters)
Python Fundamentals
Preface

The while Statement


A while statement allows you to execute a block of code repeatedly, as long as a condition remains true. That is to say, as long as condition X remains true, execute this code.

A while statement can also have an else clause that will be executed exactly once when the condition, X, that's mentioned is no longer true. This can be read as follows: As long as X remains true, execute this block of code, else, execute this other block of code immediately so that the condition is no longer true.

For instance, consider the traffic police officer we mentioned earlier, who could be letting traffic through while the exit is clear, and as soon as it is not clear, they stop the drivers from exiting.

Here is the basic syntax of a while statement:

while condition:
  # Run this code while condition is true
  # Replace the "condition" above with an actual condition
  # This code keeps running as long as the condition evaluates to True
else:
  # Run the code in here once the condition is no...