Creative Python Programming with Strype

There are many ways to read this book. You could read it sequentially, from beginning to end, and everything inbetween. Or you can jump around, dip in and out, look forward, and come back when you are missing something.

The main thing is: be curious. With the sequence of the chapters in this book, we are suggesting what we think is a sensible order of activities, but we also realise that everyone’s starting point is different. Concentrate on what interests you.

One thing, however, is crucial: Make sure to do the exercises and the practical work while you read this book. You will not get much out of it without it. Programming is a contact sport: you will not become a programmer just by reading about it. This book tries to put you in a position where you can actively do some programming tasks, but it is only in the actual doing that you will learn.

While you do the programming activities: be patient. The early chapters of the book start with easy projects, but they get quite a bit more difficult towards the end.

Spend a good amount of time with each topic. Extending the suggested projects will help you understand more. Add your own ideas, until you feel comfortable at each stage.

As you move through the book – whether it is in sequence or by jumping back and forth – pay attention to the concept summaries at the end of the chapters, and do not be afraid to go back to sections you have previously completed.

Pedagogy is the term for the art of teaching. The authors of this book have many years of experience in teaching programming, and this experience has shaped the approach of this text. This book follows a carefully designed pedagogy based on worked examples, scaffolding, a spiral approach and working from the concrete to the abstract.

Worked examples are used throughout, and all concepts are introduced and practiced via concrete projects. Emphasis is placed not only on the end product – the finished program – but also on the process of developing it.

Many textbooks follow a common pattern: A problem is presented, a solution is shown, and then the constructs used in that solution are explained. This is a terrible approach. It creates the illusion that a good programmer goes in one step from reading the problem description to writing down a fully working solution. This is not how programming works.

A result of this approach often is that learners who struggle with finding the right solution, or with making it work quickly, think they are failing. They react by developing a self-image of "I am not a good programmer" and "programming is just not for me".

The fact that we all work in small steps, try things out, run into problem, backtrack, try something different, and slowly work our way to a solution seems to be one of the best kept secrets in programming.

This is a shame.

In this book, we show not only the product, but the process of programming. With each project, we go through several phases of extension and refinement. Learners experience the process, and can follow along. We use a process of scaffolding to provide meaningful context while keeping learners focussed on the topic at hand, and fading of the scaffold and guidance over time.

At the same time, the examples are selected to be open-ended and extendable, so that learners are encouraged to take each example further in a direction of their own interest. Each chapter includes suggestions to do more.

We also use a spiral approach. When we first encounter a construct, we do not try to explain or understand everything about it. We learn what is necessary at that point, and then refine our understanding later. We come back to the concept in a different context, and then again later still – and in each iteration we deepen our understanding.

This is a more natural and useful approach to understanding programming. Firstly, many programming constructs are circularly dependent on each other, and there is no linear sequence in which everything can be explained only by backwards reference. But more importantly, when books try to explain everything about any given concept at once (think, for example: types) learners cannot usually distinguish what is needed at that moment ("what do I need to know right now?") from what is there only for completeness’s sake. The important is buried in the detail, and learning is made harder.

The spiral approach serves to break this linear form, iterate over concepts several times, and lead to a deeper understanding.

The other obvious difference of this book is the use of the Strype environment.

Strype is a browser-based educational Python development environment designed specifically for novice learners. It is free to use, and anyone can use it instantly – no creation of accounts is needed. Strype uses a frame-based editor: frame-based editing is an interaction style that combines the best of both worlds of block-based and text-based editing. It provides the discoverability and some of the error avoidance of blocks, but at the same time gives you the power and expressiveness of a full, professional language. Some of the friction of getting your programs to run is removed, and you achieve results more quickly and with less frustration. The use of Strype, and its integration in this book, are absolutely fundamental to our approach.

As we stated above, our firm goal is to make the first experience of programming engaging, fun and creative. One way to do so, for example, is the early use of graphics and animation. Yet animated graphics are much too complicated for novices to use in most Python environments.

Strype is designed to make this approach simple, painless and possible. We can create a graphic in a single line of code, and animate it in just a few lines more. The effect of program statements becomes immediately visible on screen in a way that no "Hello world" program can ever manage, and learners can observe their program execute.

The technology and the pedagogy used in this book were developed in tandem, with environment design strongly guided by our pedagogical principles. The result is a package of software, examples and explanation that is seamlessly integrated, and enables learners to achieve more satisfying results than they might with other systems.

Overall, we strongly believe that this helps the most important aspect of all: motivation. We hope to spark our readers' curiosity, to leave you wanting to read on, to continue to learn, because you have caught the programming bug just like we have.

We hope that you will see not only how programming works, but also why you might be interested in it, and what it can do for you.

We wish to thank Pierre Weill-Tessier for his work on the implementation of Strype. Pierre was, together with the authors of this book, a core member of the team that designed and implemented the Strype software. His work is present in many details of the system, and with that, he has contributed greatly to the outcome of this project.

We are also indebted to Pete Dring, who provided feedback on an early draft of this book. Pete’s feedback was incredibly valuable to us and has helped to improve this book in many places. His comments were thoughtful, detailed and specific, and the book is better because of them.