Conventions

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: "The apply function  also supports array input and matrix output."

The style of inline code words (variables and function names) and code blocks is set as follows:

x <- c(1, 2, 3)
class(x)
## [1] "numeric"
typeof(x)
## [1] "double"
str(x)
##  num [1:3] 1 2 3

There will be a highlight on certain areas of the code whenever a point is being pointed out:

x <- rnorm(100)
y <- 2 * x + rnorm(100) * 0.5
m <- lm(y ~ x)
coef(m)

New terms and important words are shown in bold. 

Note

Warnings or important notes appear in a box like this.

Tip

Tips and tricks appear like this.