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)
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Making shallow and deep copies of objects

Throughout this chapter, we've talked about how assignment statements share references to objects. Objects are not normally copied. When we write:

a = b

we now have two references to the same underlying object. If the object of b has a mutable type, like the list, set, or dict types, then both a and b are references to the same mutable object.

As we saw in the Understanding variables, references, and assignment recipe, a change to the a variable changes the list object that both a and b refer to.

Most of the time, this is the behavior we want. There are rare situations in which we want to actually have two independent objects created from one original object.

There are two ways to break the connection that exists when two variables are references to the same underlying object:

  • Making a shallow copy of the structure
  • Making a deep copy of the structure

Getting ready

Python does...