Most of the features of functional programming are already first-class parts of Python. Our goal in writing functional Python is to shift our focus away from imperative (procedural or object-oriented) techniques to as much of an extent as possible.
We'll look at each of the following functional programming topics:
- First-class and higher-order functions, which are sometimes known as pure functions.
- Immutable data.
- Strict and non-strict evaluation. We can also call this eager versus lazy evaluation.
- Recursion instead of an explicit loop state.
- Functional type systems.
This should reiterate some concepts from the first chapter: firstly, that purely functional programming avoids the complexities of an explicit state maintained through variable assignments; secondly, that Python is not a purely functional language.
This book...
