Book Image

Expert Python Programming - Fourth Edition

By : Michał Jaworski, Tarek Ziadé
Book Image

Expert Python Programming - Fourth Edition

By: Michał Jaworski, Tarek Ziadé

Overview of this book

This new edition of Expert Python Programming provides you with a thorough understanding of the process of building and maintaining Python apps. Complete with best practices, useful tools, and standards implemented by professional Python developers, this fourth edition has been extensively updated. Throughout this book, you’ll get acquainted with the latest Python improvements, syntax elements, and interesting tools to boost your development efficiency. The initial few chapters will allow experienced programmers coming from different languages to transition to the Python ecosystem. You will explore common software design patterns and various programming methodologies, such as event-driven programming, concurrency, and metaprogramming. You will also go through complex code examples and try to solve meaningful problems by bridging Python with C and C++, writing extensions that benefit from the strengths of multiple languages. Finally, you will understand the complete lifetime of any application after it goes live, including packaging and testing automation. By the end of this book, you will have gained actionable Python programming insights that will help you effectively solve challenging problems.
Table of Contents (16 chapters)
14
Other Books You May Enjoy
15
Index

Using decorators to modify function behavior before use

Decorators are one of the most common inspection-oriented metaprogramming techniques in Python. Because functions in Python are first-class objects, they can be inspected and modified at runtime. Decorators are special functions capable of inspecting, modifying, or wrapping other functions.

The decorator syntax was explained in Chapter 4, Python in Comparison with Other Languages, and is in fact a syntactic sugar that is supposed to make it easier to work with functions that extend existing code objects with additional behavior.

You can write code that uses the simple decorator syntax as follows:

@some_decorator
def decorated_function(): 
    pass 

You can also write it in the following (more verbose) way:

def decorated_function(): 
    pass 
decorated_function = some_decorator(decorated_function)

This verbose form of function decoration clearly shows what the decorator does. It takes a function object...