Introduction to R

John Bastiaansen

What is R

R is a programming environment
- Statistics
- Graphics
Why R ?
- free and runs on Windows, Linux, and MacOS
- excellent built-in help system
- easy to learn syntax with many built-in statistical functions
R is a command-line system, not a point-and-click system

CRAN

Main website of the R project : http://www.r-project.org/

Downloading R

For this course, R has been installed on your computers

When R is installed it comes with the program’s GUI (Graphical User Interface) which looks like this:

R GUI

We don’t use this GUI in our course, instead we use RStudio

For this course we use RStudio
Advantages of RStudio include
- easy management of your workspace and files
- highlighted code avoids mistakes
- integrated access to R help
Rstudio can be downloaded from : http://rstudio.org/

Rstudio interface

You can use R as a simple calculator:

(1+3)* (7-3)

## [1] 16

1024/256

## [1] 4

5^2

## [1] 25

exp(pi)-pi

## [1] 19.9991

The working directory is R’s default place to look for files, find it using function getwd:

getwd()
dir <- "~/Dropbox/Rcursus/mei2015/john/introduction/"
setwd(dir)
getwd()

## [1] "~/Dropbox/Rcursus/mei2015/john/introduction/"

Use the function help.start() to open a help browser page:

The help page

In RStudio the help pages open in the lower right panel

Use the ? operator to open a help page on an object or function:

?print to open help on the print function:

R help

In RStudio the help pages open in the lower right panel and can be expanded to full screen view

Type q() and R will quit:

Quitting R