In this book, you will find a number of styles of text 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: "A list is created using the list command, and a variable can be tested or coerced using the is.list and as.list commands."

A block of code is set as follows:

> x = rnorm(5,mean=10,sd=3)
> x
[1] 11.172719  8.784284 10.074035  5.735171 10.800138
> pnorm(abs(x-10),mean=0,sd=3)-pnorm(-abs(x-10),mean=0,sd=3)
[1] 0.30413363 0.31469803 0.01968849 0.84486037 0.21030971
>

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

> v <- c(1,3,5,7,-10)
> v
[1]   1   3   5   7 -10
> v[4]
[1] 7
> v[2] <- v[1]-v[5]
> v
[1]   1  11   5   7 -10

New terms and important words are shown in bold.