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

Reducing with operator module functions

We'll look at one more way that we can use the operator definitions. We can use them with the built-in functools.reduce() function. The sum() function, for example, can be defined as follows:

sum = functools.partial(functools.reduce, operator.add)

This creates a partially evaluated version of the reduce() function with the first argument supplied. In this case, it's the + operator, implemented via the operator.add() function.

If we have a requirement for a similar function that computes a product, we can define it like this:

prod = functools.partial(functools.reduce, operator.mul)

This follows the pattern shown in the preceding example. We have a partially evaluated reduce() function with the first argument of the * operator, as implemented by the operator.mul() function.

It's not clear whether we can do similar things with too many of the other operators. We might be able to find a use for the operator.concat() function, as well as the operator.and() and...