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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Defining position-only parameters with the / separator

In Python 3.8, an additional annotation was added to function definitions. We can use the / character in the parameter list to separate the parameters into two groups. Before /, all parameters work positionally, or names may not be used with argument values. After /, parameters may be given in order, or names may be used.

This should be used for functions where the following conditions are all true:

  • A few positional parameters are used (no more than three)
  • They are all required
  • The order is so obvious that any change might be confusing

This has always been a feature of the standard library. As an example, the math.sin() function can only use positional parameters. The formal definition is as follows:

>>> help(math.sin)
Help on built-in function sin in module math:
sin(x, /)
    Return the sine of x (measured in radians).

Even though there's an x parameter name, we can...