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

Chapter 5. Higher-Order Functions

A very important feature of the functional programming paradigm is higher-order functions. These are functions that accept functions as arguments or return functions as results. Python offers several kinds of higher-order functions. We'll look at them and some logical extensions.

As we can see, there are three varieties of higher-order functions as follows:

  • Functions that accept functions as one (or more) of their arguments
  • Functions that return a function
  • Functions that accept a function and return a function, a combination of the preceding two features

Python offers several higher-order functions of the first variety. We'll look at these built-in higher-order functions in this chapter. We'll look at a few of the library modules that offer higher-order functions in later chapters.

The idea of a function that emits functions can seem a bit odd. However, when we look at a Callable class, the class definition is a function that returns  Callable objects when evaluated...