Basics to R

Author

P K Parida

Why we are discussing R

- Why R and how it is useful for analysis and report preparation

Typical science project

Why R

- Its free! If you are a teacher, a student or a user, the benefits are obvious

- It runs on a variety of platforms including Windows, Unix and MacOS

- It provides an unparalleled platform for programming new statistical methods in an easy and straightforward manner

- It offers powerful tools for data exploration and presentation

- It has ample resources on the web

- R is open-source

Other statistical software packages can be extremely expensive
Large user base with almost all statistical methods implemented

- Import

Import data stored in a file, database, or web API, and load it into R

- Tidy

Each column is a variable, and each row is an observation

Tidy datasets are all alike but every messy dataset is messy in its own way (Hadley Wickham)

RStudio

A typical RStudio window may look something like this:

Script editor: This is where you write the code for your analysis. These could include:

R Script : An R script is basically a series of stored R commands that can be run in the console :- To generate a new script, do : New file -> R Script (ctrl-shift-N)

Rmarkdown document: A document with (or without) R-code.

Console: This is where R prints the output of your code when it’s run. You can also write code directly in the console after the > symbol, but that code is not preserved.
Environment/History: Have at minimum the following tabs:
- Environment: Displays all your obtjects (data) and user-defined functions in your current session. One can click on the objects to get a detailed view.
- History: Contains a list of previous commands entered into the console
- Additional tabs may include:
  - Connection: Any database connections
  - Build: If your project is webpage/blog project
  - Git: If your project has version control
  - Tutorial: Some nice basic tutorials on R
Files/Packages/Help/Viewer:
- Files - The list of all files contained in your current *working directory*. You can also:
```
-   Navigate to different folders on your computer
-   Create new blank files or folders (directories) 
-   Delete files or folders 
-   Rename files or folders 
-   ... More
```
- Plots - Graphical output from R. The user can export the figures to file (as jpeg, png or pdf) or to clipboard
- Packages - The list of packages (groups of functions) currently installed on your computer. You can install new packages or update existing packages from this tab by clicking Install or Update.
- Help - Search R documentation to get information what each function does and how. Using the help should be your first stop when trying to figure out how to use a particular function. The lingo may be intitially unfamiliar but with frequent use it becomes more bearable.
- Viewer: For interactive graphics