To get the most out of this book

Readers of this book should know how to execute Python programs in a development environment, or simply from a command prompt. They should also be familiar with general syntax and practices in Python programming (variables, functions, importing packages, and so on). Some basic computer science knowledge of elements such as pixels, the execution stack, and bytecode instructions is assumed at various points throughout this book.

The final section of Chapter 1, Advanced Introduction to Concurrent and Parallel Programming, covers the process of getting your Python environment set up. Chapters in this book might discuss the use of external libraries or tools that have to be installed via a package manager such as pip and Anaconda, and specific instructions on how to install those libraries are included in their corresponding chapters.

Download the example code files

You can download the example code files for this book from your account at www.packt.com. If you purchased this book elsewhere, you can visit www.packt.com/support and register to have the files emailed directly to you.

You can download the code files by following these steps:

1. Log in or register at www.packt.com.
2. Select the SUPPORT tab.
3. Click on Code Downloads & Errata.
4. Enter the name of the book in the Search box and follow the onscreen instructions.

Once the file is downloaded, please make sure that you unzip or extract the folder using the latest version of:

• WinRAR/7-Zip for Windows
• Zipeg/iZip/UnRarX for Mac
• 7-Zip/PeaZip for Linux

The code bundle for the book is also hosted on GitHub at https://github.com/PacktPublishing/Mastering-Concurrency-in-Python. In case there's an update to the code, it will be updated on the existing GitHub repository.

We also have other code bundles from our rich catalog of books and videos available at https://github.com/PacktPublishing/. Check them out!

Download the color images

We also provide a PDF file that has color images of the screenshots/diagrams used in this book. You can download it here: https://www.packtpub.com/sites/default/files/downloads/9781789343052_ColorImages.pdf.

Code in Action

Visit the following link to check out videos of the code being run: http://bit.ly/2BsvQj6

Conventions used

There are a number of text conventions used throughout this book.

CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: "The asyncio module provides a number of different transport classes."

A block of code is set as follows:

async def main(url):
    async with aiohttp.ClientSession() as session:
        await download_html(session, url)

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

urls = [
    'http://packtpub.com',
    'http://python.org',
    'http://docs.python.org/3/library/asyncio',
    'http://aiohttp.readthedocs.io',
    'http://google.com'
]

Any command-line input or output is written as follows:

> python3 example5.py
Took 0.72 seconds.

Bold: Indicates a new term, an important word, or words that you see on screen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "To download the repository, simply click on the Clone or download button in the top-right corner of your window."

Warnings or important notes appear like this.

Tips and tricks appear like this.