As detailed in the introduction, R is an ex-

tremely versatile open source programming

language for statistics and data science. It is

widely used in every field where there is data—

business, industry, government, medicine, academia,

and so on.

In this chapter, you’ll get a quick introduction to R—how to invoke it,

what it can do, and what files it uses. We’ll cover just enough to give you

the basics you need to work through the examples in the next few chapters,

where the details will be presented.

R may already be installed on your system, if your employer or univer-

sity has made it available to users. If not, see Appendix A for installation

instructions.

1.1 How to Run R

R operates in two modes: interactive and batch. The one typically used is inter-

active mode. In this mode, you type in commands, R displays results, you

type in more commands, and so on. On the other hand, batch mode does

not require interaction with the user. It’s useful for production jobs, such as

when a program must be run periodically, say once per day, because you can

automate the process.

1.1.1 Interactive Mode

On a Linux or Mac system, start an R session by typing R on the command

line in a terminal window. On a Windows machine, start R by clicking the

R icon.

The result is a greeting and the R prompt, which is the > sign. The

screen will look something like this:

R version 2.10.0 (2009-10-26)

Copyright (C) 2009 The R Foundation for Statistical Computing

ISBN 3-900051-07-0

...

Type 'demo()' for some demos, 'help()' for on-line help, or

'help.start()' for an HTML browser interface to help.

Type 'q()' to quit R.

You can then execute R commands. The window in which all this

appears is called the R console.

C0bra5; Start Time - 0:00.500; End Time - 2:59.900; Total Time - 2:59.400