Raspberry Pi User Guide, 3rd Edition

Appendix A

Python Recipes

THE FOLLOWING RECIPES provide the program code for Example 3 and Example 4 in Chapter 12, “An Introduction to Python”, and a sample solution for the combined input-output program suggested in Chapter 15, “The GPIO Port”. Each recipe is also available for download from the Raspberry Pi User Guide website at www.wiley.com/go/raspberrypiuserguide3e. If you’re typing the code by hand, look out for the ↵ symbol, which indicates that the line is wrapped because of space constraints in the book. If you see the symbol at the end of a line, don’t press Enter until you reach the end of a line that doesn’t have a symbol present.

Raspberry Snake (Chapter 12, Example 3)

#!/usr/bin/env python# Raspberry Snake# Written by Gareth Halfacree for the Raspberry Pi User Guideimport pygame, sys, time, randomfrom pygame.locals import *pygame.init()fpsClock = pygame.time.Clock()playSurface = pygame.display.set_mode((640, 480))pygame.display.set_caption('Raspberry Snake')redColour = pygame.Color(255, 0, 0)blackColour = pygame.Color(0, 0, 0)whiteColour = pygame.Color(255, 255, 255)greyColour = pygame.Color(150, 150, 150)snakePosition = [100,100]snakeSegments = [[100,100],[80,100],[60,100]]raspberryPosition = [300,300]raspberrySpawned = 1direction = 'right'changeDirection = directiondef gameOver():    gameOverFont = pygame.font.Font('freesansbold.ttf', 72)    gameOverSurf = gameOverFont.render ↵    ('Game Over', True, greyColour)    gameOverRect = gameOverSurf.get_rect()    gameOverRect.midtop ...