Book Image

Secret Recipes of the Python Ninja

Book Image

Secret Recipes of the Python Ninja

Overview of this book

This book covers the unexplored secrets of Python, delve into its depths, and uncover its mysteries. You’ll unearth secrets related to the implementation of the standard library, by looking at how modules actually work. You’ll understand the implementation of collections, decimals, and fraction modules. If you haven’t used decorators, coroutines, and generator functions much before, as you make your way through the recipes, you’ll learn what you’ve been missing out on. We’ll cover internal special methods in detail, so you understand what they are and how they can be used to improve the engineering decisions you make. Next, you’ll explore the CPython interpreter, which is a treasure trove of secret hacks that not many programmers are aware of. We’ll take you through the depths of the PyPy project, where you’ll come across several exciting ways that you can improve speed and concurrency. Finally, we’ll take time to explore the PEPs of the latest versions to discover some interesting hacks.
Table of Contents (17 chapters)
Title Page
Copyright and Credits
Packt Upsell
Foreword
Contributors
Preface
Index

Increasing accuracy with fractions


The fractions module adds support for rational number arithmetic to Python. Rather than using x/y to represent a fraction, true, precise fractions can be written; the former method returns a float type which may or not not be truly accurate.

A constructor is available to create a fraction from integer pairs, from another fraction, a float, a decimal, or a string. If the denominator is 0, a ZeroDivisionError is generated.

How to do it...

The following properties and methods are available for the fractions class:

  • numerator: This returns the numerator in the lowest term.
  • denominator: This returns the denominator in the lowest term.
  • from_float(float): This is constructor that takes a float type and creates a fraction representing the exact value of the argument. It's generally easier to just make a fraction instance directly from a float.
  • from_decimal(dec): This is a constructor that takes a decimal instance and creates a fraction representing the exact value of the...