Introduction 1

RStudio

How to work in R

Let’s create a script, a “text” file where you write and save your code.

How to work in R

Let’s save it:

Working Environment

RStudio is divided into 4 main panes:

RStudio is divided into 4 main panes:

• Script. The text file where you write and save your code. You can run one line at a time (Ctrl + Enter / Cmd + Enter) or the whole script by clicking Source. Comments are added with #.

• Console. This is where R runs the code and shows the results. You can type commands directly in the console for quick tests, but they are not saved.

• Environment / Temporary desk. Shows all the objects created during the current session.

• Miscellaneous. A multi-purpose pane with several tabs, including the file explorer.

Working Directory

The location (folder) on your PC where R is working and where R expects to find your files, unless specified otherwise.

getwd()

[1] "/Users/tita/course-R-2425/materials/1_intro"

Absolute Path

PC

|- Users
    |
    |- tita
        |
        |- course-R-2425
            |
            |- materials
                |
                |- 1_intro

I am working inside the 1_intro folder.

Relative Path (to the working directory)

1. Change the working directory with the setwd command:

setwd('/Users/tita/Desktop/introR')

2. Download the file prova.csv and put it in the folder.

3. Since we are working inside the folder, if we want to load a file located in this folder we can simply write the file name in quotes and use, for example, the read.csv function:

data <- read.csv("prova.csv")

Now move the prova.csv outside the introR folder (e.g., in the desktop), and run the same command..

data <- read.csv("prova.csv")

If we want to load a file located outside our wd, we need to refer to it through its absolute path:

data <- read.csv("/Users/tita/Desktop/prova.csv")

Or, first change the working directory with the setwd command and then load the file.

setwd('/Users/tita/Desktop')
data <- read.csv("prova.csv")

The best solution?

Create an R project!

• they set the working directory automatically
• they let you use relative paths instead of absolute paths
• they give quick access to a given project

Let’s create one!