Book Image

Modern Python Cookbook

Book Image

Modern Python Cookbook

Overview of this book

Python is the preferred choice of developers, engineers, data scientists, and hobbyists everywhere. It is a great scripting language that can power your applications and provide great speed, safety, and scalability. By exposing Python as a series of simple recipes, you can gain insight into specific language features in a particular context. Having a tangible context helps make the language or standard library feature easier to understand. This book comes with over 100 recipes on the latest version of Python. The recipes will benefit everyone ranging from beginner to an expert. The book is broken down into 13 chapters that build from simple language concepts to more complex applications of the language. The recipes will touch upon all the necessary Python concepts related to data structures, OOP, functional programming, as well as statistical programming. You will get acquainted with the nuances of Python syntax and how to effectively use the advantages that it offers. You will end the book equipped with the knowledge of testing, web services, and configuration and application integration tips and tricks. The recipes take a problem-solution approach to resolve issues commonly faced by Python programmers across the globe. You will be armed with the knowledge of creating applications with flexible logging, powerful configuration, and command-line options, automated unit tests, and good documentation.
Table of Contents (18 chapters)
Title Page
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Using settable properties to update eager attributes


In several of the previous recipes, we've looked at the important distinction between eager and lazy computation. See the Designing classes with lots of processing recipe for an example of eagerly computing a result and setting object attributes. See the Using properties for lazy attributes recipe for a way to use properties to lazily compute a result.

When an object is stateful, then attribute values must be changed throughout the object's life. It's common to use methods to eagerly compute attribute changes, but this isn't really necessary.

We have the following choices for stateful objects:

  • Set attribute values via methods:
    • Compute results eagerly, putting results in attributes
    • Compute results lazily, using properties that have syntax that looks like a simple attribute
  • Set values via attributes:
    • If results are computed lazily via properties, then the new state can be reflected in these calculations

What can we do if we want to use attribute...