This book requires a basic knowledge of machine learning and Python coding. Moreover, a university-level knowledge of probability theory, calculus, and linear algebra is needed in order to have a full understanding of all theoretical discussions. However, readers who are not familiar with such concepts can skip the mathematical discussions and focus only on the practical aspects. Whenever needed, reference to specific papers and books is provided so as to allow a deeper understanding of the most complex concepts.

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/HandsOn-Unsupervised-Learning-with-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!

We also provide a PDF file that has color images of the screenshots/diagrams used in this book. You can download it here: http://www.packtpub.com/sites/default/files/downloads/9781789348279_ColorImages.pdf.

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: "Mount the downloaded WebStorm-10*.dmg disk image file as another disk in your system."

A block of code is set as follows:

X_train = faces['images']
X_train = (2.0 * X_train) - 1.0

width = X_train.shape[1]
height = X_train.shape[2]

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

import tensorflow as tf

session = tf.InteractiveSession(graph=graph)
tf.global_variables_initializer().run()

Bold: Indicates a new term, an important word, or words that you see onscreen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "Select System info from the Administration panel."