Book Image

Learning Python Application Development

By : Ninad Sathaye
Book Image

Learning Python Application Development

By: Ninad Sathaye

Overview of this book

Python is one of the most widely used dynamic programming languages, supported by a rich set of libraries and frameworks that enable rapid development. But fast paced development often comes with its own baggage that could bring down the quality, performance, and extensibility of an application. This book will show you ways to handle such problems and write better Python applications. From the basics of simple command-line applications, develop your skills all the way to designing efficient and advanced Python apps. Guided by a light-hearted fantasy learning theme, overcome the real-world problems of complex Python development with practical solutions. Beginning with a focus on robustness, packaging, and releasing application code, you’ll move on to focus on improving application lifetime by making code extensible, reusable, and readable. Get to grips with Python refactoring, design patterns and best practices. Techniques to identify the bottlenecks and improve performance are covered in a series of chapters devoted to performance, before closing with a look at developing Python GUIs.
Table of Contents (18 chapters)
Learning Python Application Development
Credits
Disclaimers
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Defining custom exceptions


You can define your own exception class by inheriting from the Exception base class or any other exception class. Why do we need such customization? Firstly, you can create an exception class with a descriptive name. This allows us to identify the purpose of the exception just by looking at the descriptive name. For example, instead of ValueError, a custom exception named ValueGreaterThanFiveError will immediately help identify the problem. There are other advantages as well. You can use such classes to add customized messages based on error subcategories, writing error logs, and so on. Let's learn how to define custom exceptions next.

Preparatory work

Here is a list of files we will use:

  • attackoftheorcs_v1_1.py: This is the file from the previous section that we will use. As mentioned earlier, the supporting code bundle already has a file by the same name. It includes all the modifications we will discuss.

  • gameuniterror.py: This is a new module to hold a custom...