Why functional programming in Python matters: Interview with best selling author, Steven Lott

About Steven

Steven F. Lott has been programming since the 70s, when computers were large, expensive, and rare. As a contract software developer and architect, he has worked on hundreds of projects, from very small to very large. He's been using Python to solve business problems for over 10 years. Steven is a technomad who lives in various places on the east coast of the U.S. Follow his technology blog to stay updated on the latest trends in tech. You may also connect with him on LinkedIn.

Key Takeaways

• Why learn Python? One of the major reasons developers appreciate Python, is because it’s simple, and has the ability to create succinct and expressive programs. For example, data scientists prefer Python because they can build sophisticated analytical tools using simple functions and produce useful results.
• Why Functional programming? The functional programming paradigm forms the perfect foundation for developers and architects to build and design modern architectures like Serverless.
• But Python isn’t inherently functional. Although an object oriented language at heart, Python can create higher order functions and other functional features. Python 3 has made this easier.
• Steven’s Python 4 wish list: In future versions of Python, Steven hopes to see a wider use of Unicode operator characters like × in addition, * for multiplication, and ÷ in addition to / for division. Also, he expects PyPy and RPython projects to be more widely used; future Pythons versions will benefit from optimizations and restructuring the interpreter.
• One of the most helpful features of Python 3 are type hints, which allow one to write clear and implicitly documented code while preventing the invoking of methods with wrong data types. Steven’s latest edition of Functional programming with Python, explores type hints in depth along with core language features such as lambdas, generator expressions, functions, and callable objects.

Full Interview

Python is one of the top programming languages. List down top 3 features of Python that make programmers love it..

• It seems like programmers love Python primarily because it allows them to create succinct, expressive programs.
• Before long, they learn the vast library of code - is another reason for Python's immense popularity.
• Many people adopt Python because of the low barrier to entry: it really is as simple as download and start working.

You've been working with Python for over a decade. How has your experience been with Python as a primary development language?

Over my 40-year career, I've used a variety of languages. And I've found Python to be extremely productive. A team can build and deploy microservices-based applications at a tremendous pace. Data scientists can build sophisticated analytical tools using simple functions to produce useful results without the overheads of complex compile and build environments.

Back when Python 3 just came into existence, we saw certain resistance to the notion of Python being apt for functional programming. How would you say Python has progressed since then?

At its core, Python is an object-oriented language. Consequently some functional features aren't central. One of the essential functional design tools -- creating higher-order functions -- has always been part of Python. The wider use of generator functions in Python 3 has made functional Python programming much more common. Many Python applications are hybrids, mixing object-oriented and functional features of the language. Now that type hints are available, it becomes practical to use mypy to confirm that the code is very likely to work properly.

For a developer who's picking up the Functional Programming paradigm for the first time, what do you think are the prerequisites?

Functional programming is closely aligned to the core mathematical ideas of functions and functional composition. As a consequence, a minimal background in programming could be advantageous to help leverage essential function definitions and avoid needless state change. For programmers already heavily invested in procedural programming, it may be helpful to set the idea of stateful objects aside.

In the above context, how does your book, Functional Python Programming, Second Edition, prepare its readers to be industry ready? What are the key takeaways for readers from your title and how does it help with the learning curve?

The examples in the book are related to exploratory data analysis, an important skill in the broader area of data science. They also focus on the standard library, allowing someone to apply the functional design approach to other libraries and tools. I think a focus on the core language features (e.g., lambdas, generator expressions, functions, callable objects) provide a foundation that allows a programmer to apply the core ideas more widely to different kinds of problems and other software packages.

What new and updated content is available in this edition, for developers who've purchased your previous book?

Almost all of the examples have been rewritten to include type hints. This can be an important quality check helping to ensure the Python code works. When used with doctest examples, it becomes relatively easy to provide reliable, correct code. In a few cases, external packages (i.e., the pymonad library) don't have type hints and the examples reflect this gap.

Can you throw some light on Functional Reactive Programming and how FRP with Python is boosting the implementation of modern architectures like Cloud Native and Serverless?

The central idea of serverless programming -- a collection of isolated functions -- fits the functional programming paradigm very elegantly. The processing is generally stateless, with stand-alone functions waiting for their inputs. Ideas like "choreography" of web services work with this idea of stateless functions that respond to an input by producing an output. This leads to careful separation of persistence and state change from the other transformational processing. This helps create software with easy-to-understand behavior and implementation code that's very expressive of the algorithm.

As Python inches towards a 4.0, what do you think should/can be changed/rectified in the language, for the better?

At some point, I expect the PyPy and RPython projects to create some optimizations leading to a fundamental restructuring of the interpreter. Perhaps these changes could remove the need for the GIL (Global Interpreter Lock) by exposing a minimal kernel of code that requires exclusive access to internal data structures.

Of more general interest, I'd hope to see wider use of Unicode operator characters like × in addition to * for multiplication, and ÷ in addition to / for division. Perhaps ∻ could be adopted for truncated division. This could also lead to use of ℝ instead of float and ℤ instead of int providing a more mathematical look to type hints. It would be nice to expand the use of the Unicode character set to create more readable programs.

List down 3 reasons for developers to choose your book as the book of choice for Functional programming in Python.

• Programmers who want to create succinct and expressive code often find functional design to help them fulfill this. The Functional Python Programming book provides extensive examples that show multiple ways to achieve this goal.
• In many cases, generator functions and lazy processing can be a large performance improvement. A generator function can use less memory than a large data collection, and this change can be helpful. This book will provide number of examples of lazy processing to avoid creating large, in-memory collections.
• It can be difficult to get started with type hints. The use case in this book show type hints in somewhat more complex real-world situations.

If you enjoyed this interview, head over to check out Steven’s latest edition of Functional Python Programming, He is leveraging Python to implement microservices and ETL pipelines. His other titles with Packt Publishing include Python Essentials, Mastering Object-Oriented Python, Functional Python Programming, and Python for Secret Agents.

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