Indholdsfortegnelse for The Python Book 2nd Edition i The Python Book

Resources Python 2: www.python.org/download IDLE: www.python.org/idle This tutorial will guide you through making a rock, paper, scissors game in Python. The code applies the lessons from the masterclass – and expands on what was included there – and doesn’t require any extra Python modules to run, like Pygame. Rock, paper, scissors is the perfect game to show off a little more about what exactly Python can do. Human input, comparisons, random selections and a whole host of loops are used in making a working version of the game. It’s also easy enough to adapt and expand as you see fit, adding rules and results, and even making a rudimentary AI if you wish. For this particular tutorial, we also recommend using IDLE. IDLE is a great Python IDE that is…

Resources Python 2: www.python.org/download IDLE: www.python.org/idle The three basic games we have made in Python so far have all run in the command line or via IDLE, a Python IDE. While this allowed us to show off different ways to use Python code, we haven’t actually shown you how to present it yet. In this tutorial, we will take all three games and put them all into one neatly unified graphical interface. To this end, we’ll be making use of the small line of code we added at the bottom of each previous tutorial so we can import them as modules into our main graphical script. We’ll also modify the existing code to add some graphical elements. To do all this we’ll be using Tkinter, a default module available in…

Raspberry Pi While we haven’t discussed what kind of computer to use for your robotics project, you should consider the famous Raspberry Pi. This tiny computer should be small enough to fit into almost any robot structure that you might be building. Since it is already running Linux and Python, you should be able to simply copy your code development work to the Pi. It also includes its own IO bus so that you can have it read it’s own sensors. Arduino In contrast to the Raspberry Pi, which runs a full OS from its SD card, the Arduino boards are microcontrollers rather than complete computers. Instead of running an OS, the Arduino platform executes code that is interpreted by its firmware. It is mainly used to interface with hardware…

Resources NumPy: www.numpy.org SciPy: www.scipy.org Matplotlib: www.matplotlib.org NumPy is the primary Python package for performing scientific computing. It has a powerful N-dimensional array object, tools for integrating C/C++ and Fortran code, linear algebra, Fourier transform, and random number capabilities, among other things. NumPy also supports broadcasting, which is a clever way for universal functions to deal in a meaningful way with inputs that do not have exactly the same form. Apart from its capabilities, the other advantage of NumPy is that it can be integrated into Python programs. In other words, you may get your data from a database, the output of another program, an external file or an HTML page and then process it using NumPy. This article will show you how to install NumPy, make calculations, plot data,…

Resources Raspbian: www.raspberrypi.org/ downloads Python: www.python.org/doc Pygame: www.pygame.org/docs When you’re learning to program in a new language or trying to master a new module, experimenting with a familiar and relatively simply project is a very useful exercise to help expand your understanding of the tools you’re using. Our Space Invaders clone is one such example that lends itself perfectly to Python and the Pygame module – it’s a simple game with almost universally understood rules and logic. While the Invaders meander their way down the screen towards you, it’s your job to pick them off while dodging their random fire. When one wave is conquered, another faster, more aggressive wave appears. We’ve tried to use many features of Pygame, which is designed to make the creation of games and interactive…

Resources Pygame Zero: pygame-zero.readthedocs.org Pygame: pygame.org/download.shtml Pip pip-installer.org Python 3.2 or later www.python.org/Code from FileSilo (optional) Games are a great way of understanding a language: you have a goal to work towards, and each feature you add brings more fun. However, games need libraries and modules for graphics and other essential games features. While the Pygame library made it relatively easy to make games in Python, it still brings in boilerplate code that you need before you get started – barriers to you or your kids getting started in coding. Pygame Zero deals with all of this boilerplate code for you, aiming to get you coding games instantly. Pg0 (as we’ll abbreviate it) makes sensible assumptions about what you’ll need for a game – from the size of the window…

Resources Python Source Code www.python.org/download/releases/2.7.2 Django Source Code www.djangoproject.com/download Creating your own blog always feels like a great accomplishment. Sure, you could use the fantastic WordPress if you need a complete blog with every feature you’d ever need right now. And Tumblr exists for people who just want to write something, or post pictures of corgis in space. You don’t have full control from start to finish with a prefabricated blog, though, and neither of these is written in the fantastic Django. Django is of course based on Python, the objectorientated programming language designed to have clearly readable syntax. Due to its Python base, it’s an incredibly powerful and simple-touse language for web development with a vast array of applications. So let’s use it to make a blog. In this…

Resources A Raspberry Pi with all necessary peripherals An SD card containing the latest Debian image for the Raspberry Pi http://www.raspberrypi.org/downloads This tutorial follows on from the one last issue: ‘Setting up the Raspberry Pi’, where we showed you how to prepare your SD card for use with the Raspberry Pi. The beauty of using an SD card image is that the operating system is ready to go and a development environment is already configured for us. We’ll be using a lightweight integrated development environment (IDE) called Geany to do our Python development. Geany provides a friendlier interface compared to text-based editors such as nano and will make it easier to get into the swing of things. This tutorial will cover topics such as: • basic arithmetic • comparison operators,…

Python is a great programming language for both beginners and experts. It is designed with code readability in mind, making it an excellent choice for beginners who are still getting used to various programming concepts. The language is popular and has plenty of libraries available, allowing programmers to get a lot done with relatively little code. You can make all kinds of applications in Python: you could use the Pygame framework to write simple 2D games, you could use the GTK libraries to create a windowed application, or you could try something a little more ambitious like an app such as creating one using Python’s Bluetooth and Input libraries to capture the input from a USB keyboard and relay the input events to an Android phone. For this guide we’re…

Resources Python 2: www.python.org/download IDLE: www.python.org/idle We have now created a simple selector for the trio of Python games we made previously. This interface was able to launch a GUI for our rock, paper, scissors game, and run the other two in the terminal. Now, we’re going to convert the hangman and poker dice codes to work in a similar way to rock, paper, scissors. The trick with hangman comes in allowing for a different type of input, text, and the ability to have multiple rounds of the game. Tkinter allows for text entry, and we rely a lot less on ‘while’ loops to play the game in its entirety. Poker Dice needs to keep the dice analysis code, and the option to change specific dice using checkboxes. We’ll be…

Resources A computer – running your favourite Linux distribution Internet connection – to access documentation Python 2.x, PyGTK and GObject – packages installed He’re we’ll be implementing an instant messenger in Python with a client-server architecture. This means each client connects to the server, which relays any message that one client sends to all other clients. The server will also notify the other clients when someone joins or leaves the server. The instant messenger can work anywhere a TCP socket can: on the same computer with the loopback interface, across various computers on a LAN, or even over the internet if you were to configure your router correctly. However, our messages aren’t encrypted, so we wouldn’t recommend that. Writing an instant messenger is an interesting technical problem that covers a…

Resources Raspbian: www.raspberrypi.org/downloads Python: www.python.org/doc Pygame: www.pygame.org/docs Art assets: opengameart.org We had great fun creating our basic Space Invaders clone, Pivaders, for the previous tutorial. One of the key challenges with the project was keeping it to a manageable size – just 300 lines of Python. Without the use of Pygame’s strong set of features, that goal would likely have been overshot at least twofold. Pygame’s ability to group, manage and detect collisions thanks to the Sprite class really made a great difference to our project, not just in terms of length but in simplicity. If you missed the first part of the project, you can find the v0.1 code listing on GitHub via git.io/cBVTBg, while you can find version v0.2, including all the images, music and sound effects we…

Why? First released in 1991, companies like Google and NASA have been using Python for years Thanks to the introduction of the Web Server Gateway Interface (WSGI) in 2003, developing Python web apps for general web servers became a viable solution as opposed to restricting them to custom solutions. Python executables and installers are widely available from the official Python site at www.python.org. Mac OS X users can also benefit greatly from using Homebrew to install and manage their Python versions. Whilst OS X comes bundled with a version of Python, it has some potential drawbacks. Updating your OS may clear out any downloaded packages, and Apple’s implementation of the library differs greatly from the official release. Installing using Homebrew helps you to keep up to date and also means…

Resources Python base: http://www.python.org/download/ Django source: https://www. djangoproject.com/download/ In the last tutorial we began to build the most basic of blogs, and learned how to use a bit of Django in the process. We can now set up a new project, create a database and write basic code to read and write to the database. All simple stuff, but of course it’s core to building websites where Django might be called upon. Here we will give the front end of the site an overhaul, making it more of the standard you would expect from a modern blog. This will include a sidebar, pages, post pages and the ability to add and moderate comments. In the process we will learn some more of the benefits that come with using Django to…

Resources Hard drive OSMC: osmc.tv/ Home network Another Linux computer, less than eight years old What have you done with your Raspberry Pi camera lately? While it gives us plenty of new ways to use the Pi, unless you’ve got your computer set up as a security webcam or you’re particularly a fan of time-lapse photography, the chances are that you’ve overlooked the Pi camera module for a while. If you’re a fan of animation or you simply want to extend the possibilities of the module, why not build a stop-motion camera? By using Python and an external button to capture images, the Raspberry Pi can be the perfect tool for animators. Better still, you can go beyond animating toys or bits of LEGO and go old school by mounting…

Resources Breadboard & wires 16x16 LED Matrix 2x 74HC238 2x 74HC244 16x 220 Ohm Resistor Source code: FileSilo.co.uk Driving LEDs in an efficient fashion is a science of its own. The common availability of single-board computers has put the necessary technology within reach of everyone. When dealing with LED displays, two different systems must be considered. We will focus on traditional matrixbased systems made up of one or more LEDs. Their affordable nature makes them ideally suited to classic display applications: they communicate currency prices, provide stock-brokers with updates from the trading floor and have even been used as basic displays for primitive oscilloscopes. Finally, we will also provide you with an overview of electronic basics. This tutorial is a bit more advanced than the ones we usually run in…

Resources Python 2: www.python.org/download IDLE: www.python.org/idle So you’ve learnt how to program tic-tac-toe and guessed your way to victory at hangman. Now it’s time to head to Las Vegas and play our cards right. Or in this case, virtual dice, and more like Reno as we continue with our Python game tutorials and introduce you to some poker dice. We’re again using some of the lessons we’ve already learnt, including random number generation, list creation and modification, human input, rule setting, scoring and more. But we’ll also be adding some new skills in this tutorial. Namely, we’ll be creating and appending lists with random numbers, and using functions multiple times in one block of code to cut down on bloat. Again, we recommend using IDLE, and we’re using Python 2…

The great thing about Kivy is there are loads of directions we could take it in to do some pretty fancy things. But, we're going to make a beeline for one of Kivy's coolest features-the ability it affords you to easily run your programs on Android. We'll approach this by first showing how to make a new app, this time a dynamic Breakout style game. We'll then be able to compile this straight to an Android APK that you can use just like any other. Of course, once you have mastered the basic techniques you aren't limited to using any particular kind of app, as even on Android you can make use of all your favourite Python libraries to make any sort of program you like. Once you've mastered Kivy,…

For a lot of scientific problems, you need to play with your data in an interactive way. The original way you would do this was to use the Ipython web notebook. This project has since been renamed Jupyter. For those who have used a program like Mathematica or Maple, the interface should seem very familiar. Jupyter starts a server process, by default on port 8888, and then will open a web browser where you can open a worksheet. Like most other programs of this type, the entries run in chronological order, not in the order that they happen on the worksheet. This can be a bit confusing at first, but it means that if you go to edit an earlier entry, all of the following entries need to be re-executed…

Resources XBMC: www.xbmc.org/download Python 2.7x Python IDE (optional) Code on FileSilo XBMC is perhaps the most important thing that has ever happened in the open source media centre space. It started its life on the original Xbox videogames console and since then it has become the de facto software for multimedia aficionados. It also has been forked into many other successful media centre applications such as Boxee and Plex. XBMC has ultimately grown into a very powerful open source application with a solid community behind it. It supports almost all major platforms, including different hardware architectures. It is available for Linux, Windows, Mac OS X, Android, iOS and Raspberry Pi. In these pages we will learn to build extensions for XBMC. Extensions are a way of adding features to XBMC…

Resources Python 2.7+ Flask 0.10.0: flask.pocoo.org/ Flask Github: github.com/mitsuhiko/flask A Twilio account: twilio.com Twilio’s Python REST API Helper Library: github.com/twilio/twilio-python/zipball/master MySQLDB: mysql-python.sourceforge.net Telephony is one of the most versatile technologies in our households. Despite being invented over 100 years ago, we still use the same basic infrastructure that once only carried the voices of people to deliver a rich multitude of media content at incredible speeds. As is often the case with wonderful things, they can often be complex too – and yet phones are more important now to our daily lives than ever. So, what can we do to leverage some of that versatile technology? Well, for starters we can use an API. Twilio has created a RESTful API that removes a great deal of that complexity of telephony…

Resources Python 2: www.python.org/ Pygame: pygame.org/download.shtml IDLE Python IDE Game assets Code from FileSilo (optional) Most people look for a compelling story in modern videogames, and those that don’t have one are appearing less and less. A great way to tell a pure story is through the genre of visual novels, and you can make one fairly simply in Python. These interactive novels are an extremely popular form of entertainment in Japan, and usually work by having the player click through a story and make decisions as they go along in order to experience different plot points and endings. In Python, this is a relatively simple project to create, but with the addition of the Pygame module we can make it easier still, and even more expandable for the future.…

Resources Python 2.7+ Flask 0.10.0: flask.pocoo.org Flask GitHub: github.com/mitsuhiko/flask A Twitter account Your favourite text editor Code downloaded from FileSilo Python and Flask are a great combination when you’re looking to handle the Twitter OAuth process and build requests to obtain tokens. We’ve used Twitter here because of the large amount of easily digestible data available on it. However, since Twitter adheres to the standards set out by OAuth 1.0, the code we’ve used to sign and build requests can be modified to work with any third-party API using the same standard without a great deal of work. For years PHP has been a mainstay of template generation, but now with welldocumented frameworks such as Flask, Sinatra and Handlebars, the ability to use powerful scripting languages greatly improves our ability…

YOUR BONUS RESOURCES ON FILESILO WITH THIS BOOKAZINE, FREE AND EXCLUSIVE FOR THE PYTHON BOOK READERS, YOU’LL FIND A WEALTH OF RESOURCES, INCLUDING THE FOLLOWING… • A walkthrough video on writing goodquality code with Python from the very beginning • A series of tutorials on making a PiSnake game with Raspberry Pi and Python • A guide to using GUI with GTK • Everything you need to complete the tutorials in this book and become a Python expert filesilo.co.uk/bks-864…