Book Image

Modern Python Cookbook. - Second Edition

By : Steven F. Lott
Book Image

Modern Python Cookbook. - Second Edition

By: Steven F. Lott

Overview of this book

Python is the preferred choice of developers, engineers, data scientists, and hobbyists everywhere. It is a great language that can power your applications and provide great speed, safety, and scalability. It can be used for simple scripting or sophisticated web applications. By exposing Python as a series of simple recipes, this book gives you insight into specific language features in a particular context. Having a tangible context helps make the language or a given standard library feature easier to understand. This book comes with 133 recipes on the latest version of Python 3.8. The recipes will benefit everyone, from beginners just starting out with Python to experts. You'll not only learn Python programming concepts but also how to build complex applications. The recipes will touch upon all necessary Python concepts related to data structures, object oriented programming, functional programming, and statistical programming. You will get acquainted with the nuances of Python syntax and how to effectively take advantage of it. By the end of this Python book, you will be equipped with knowledge of testing, web services, configuration, and application integration tips and tricks. You will be armed with the knowledge of how to create applications with flexible logging, powerful configuration, command-line options, automated unit tests, and good documentation.
Table of Contents (18 chapters)
16
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17
Index

Understanding variables, references, and assignment

How do variables really work? What happens when we assign a mutable object to two variables? We can easily have two variables that share references to a common object; this can lead to potentially confusing results when the shared object is mutable.

We'll focus on this principle: Python shares references; it doesn't copy data.

To see what this rule on reference sharing means, we'll create two data structures: one is mutable and one is immutable.

Getting ready

We'll create two data structures; one is mutable and one is immutable. We'll use two kinds of sequences, although we could do something similar with two kinds of sets:

>>> mutable = [1, 1, 2, 3, 5, 8]
>>> immutable = (5, 8, 13, 21)

We'll look at what happens when references to these objects are shared.

We can do a similar comparison with a set and a frozenset. We can't easily do this...