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: "Of course, we cannot actually use the library() function until we have installed the packages."

A block of code is set as follows:

## uncomment to install the checkpoint package
## install.packages("checkpoint")
library(checkpoint)

checkpoint("2016-02-20", R.version = "3.2.3")

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

performance.outsample[,-4]
  Size Maxit Shuffle Accuracy AccuracyLower AccuracyUpper
1   40    60   FALSE     0.93          0.92          0.94
2   20   100   FALSE     0.92          0.91          0.93
3   20   100    TRUE     0.92          0.91          0.93
4   50   100   FALSE     0.91          0.90          0.92
5   50   100   FALSE     0.92          0.91          0.93

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

h2oiris <- as.h2o(
  droplevels(iris[1:100, ]))

New terms and important words are shown in bold.