Book Image

Functional Python Programming - Second Edition

By : Steven F. Lott
Book Image

Functional Python Programming - Second Edition

By: Steven F. Lott

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

Writing higher-order functions

We can identify three varieties of higher-order function; they are as follows:

  • Functions that accept a function as one of their arguments.
  • Functions that return a function. A Callable class is a common example of this. A function that returns a generator expression can be thought of as a higher-order function.
  • Functions that accept and return a function. The functools.partial() function is a common example of this. We'll save this for Chapter 10, The Functools Module. A decorator is different; we'll save this for Chapter 11, Decorator Design Techniques.

We'll expand on these simple patterns using a higher-order function to also transform the structure of the data. We can do several common transformations, such as the following:

  • Wrap objects to create more complex objects
  • Unwrap complex objects into their components
  • Flatten a structure
  • Structure a flat sequence

A Callable class object is a commonly used example of a function that returns a callable object. We'll look...