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
Other Books You May Enjoy
17
Index

Controlling the order of dictionary keys

In the Creating dictionaries – inserting and updating recipe, we looked at the basics of creating a dictionary object. In many cases, we'll put items into a dictionary and fetch items from a dictionary individually. The idea of an order to the keys isn't central to using a dictionary.

Here are two common cases where key order may be important:

  • Entry order: When working with documents in JSON or YAML notation, it can help to preserve the order of keys from the source documents.
  • Sorted order: When summarizing data, it often helps to provide the keys in some easier-to-visualize order.

A Python dictionary's keys – since version 3.6 – are saved in the order in which they were initially inserted. This can be made explicit using the collections.OrderedDict class instead of the built-in dict class.

In the case when a dictionary contains a summary, we may want to sort...