Book Image

Python Programming with Raspberry Pi

By : Sai Yamanoor, Srihari Yamanoor
Book Image

Python Programming with Raspberry Pi

By: Sai Yamanoor, Srihari Yamanoor

Overview of this book

Raspberry Pi Zero is a super-small and super-affordable product from Raspberry Pi that is packed with a plethora of features and has grabbed the notice of programmers, especially those who use Python. This step-by-step guide will get you developing practical applications in Python using a Raspberry Pi Zero. It will become a valuable resource as you learn the essential details of interfacing sensors and actuators to a Raspberry Pi, as well as acquiring and displaying data. You will get started by writing a Python program that blinks an LED at 1-second intervals. Then you will learn to write simple logic to execute tasks based upon sensor data (for example, to control a motor) and retrieve data from the web (such as to check e-mails to provide a visual alert). Finally, you will learn to build a home automation system with Python where different appliances are controlled using the Raspberry Pi. The examples discussed in each chapter of this book culminate in a project that help improve the quality of people’s lives.
Table of Contents (17 chapters)
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Dictionaries


A dictionary (https://docs.python.org/3.4/tutorial/datastructures.html#dictionaries) is a data type that is an unordered collection of key and value pairs. Each key in a dictionary has an associated value. An example of a dictionary is:

    >>> my_dict = {1: "Hello", 2: "World"}
    >>> my_dict

    {1: 'Hello', 2: 'World'}

A dictionary is created by using the braces {}. At the time of creation, new members are added to the dictionary in the following format: key: value (shown in the preceding example). In the previous example 1 and 2 are keys while 'Hello' and 'World' are the associated values. Each value added to a dictionary needs to have an associated key.

The elements of a dictionary do not have an order i.e. the elements cannot be retrieved in the order they were added. It is possible to retrieving the values of a dictionary by iterating through the keys. Let's consider the following example:

>>> my_dict = {1: "Hello", 2: "World", 3: "I", 4: "am...