Book Image

Functional Python Programming. - Second Edition

Book Image

Functional Python Programming. - Second Edition

Overview of this book

If you’re a Python developer who wants to discover how to take the power of functional programming (FP) and bring it into your own programs, then this book is essential for you, even if you know next to nothing about the paradigm. Starting with a general overview of functional concepts, you’ll explore common functional features such as first-class and higher-order functions, pure functions, and more. You’ll see how these are accomplished in Python 3.6 to give you the core foundations you’ll build upon. After that, you’ll discover common functional optimizations for Python to help your apps reach even higher speeds. You’ll learn FP concepts such as lazy evaluation using Python’s generator functions and expressions. Moving forward, you’ll learn to design and implement decorators to create composite functions. You'll also explore data preparation techniques and data exploration in depth, and see how the Python standard library fits the functional programming model. Finally, to top off your journey into the world of functional Python, you’ll at look at the PyMonad project and some larger examples to put everything into perspective.
Table of Contents (22 chapters)
Title Page
Packt Upsell
Contributors
Preface
Index

Decorators as higher-order functions


The core idea of a decorator is to transform some original function into another form. A decorator creates a kind of composite function based on the decorator and the original function being decorated.

A decorator function can be used in one of the two following ways:

  • As a prefix that creates a new function with the same name as the base function as follows:
@decorator
def original_function():
    pass
  • As an explicit operation that returns a new function, possibly with a new name:
def original_function():
    pass
original_function = decorator(original_function)  

These are two different syntaxes for the same operation. The prefix notation has the advantages of being tidy and succinct. The prefix location is more visible to some readers. The suffix notation is explicit and slightly more flexible.

While the prefix notation is common, there is one reason for using the suffix notation: we may not want the resulting function to replace the original function. We...