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

Designing recursive functions around Python's stack limits


Some functions can be defined clearly and succinctly using a recursive formula. There are two common examples:

The factorial function:

The rule for computing Fibonacci numbers:

Each of these involves a case that has a simple defined value and a case that involves computing the function's value based on other values of the same function.

The problem we have is that Python imposes a limitation on the upper limit for these kinds of recursive function definitions. While Python's integers can easily represent 1000!, the stack limit prevents us from doing this casually.

Computing Fn Fibonacci numbers involves an additional problem. If we're not careful, we'll compute a lot of values more than once:

F5 = F4 + F3

F5 = (F3 + F2) + (F2 + F1)

And so on.

To compute F5, we'll compute F3 twice, and F2 three times. This is extremely costly.

Getting ready

Many recursive function definitions follow the pattern set by the factorial function. This is sometimes...