In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "We can include other contexts through the use of the include directive."

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

# comparing cluster labels with actual iris  species labels.
table(iris$Species, clusters$cluster)

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "From recommendations related to Who to follow on Twitter to Other movies you might enjoy on Netflix to Jobs you may be interested in on LinkedIn, recommender engines are everywhere and not just on e-commerce platforms."