Working with R

• The R Console “interprets” whatever you type
  • Calculator
  • Creating variables
  • Applying functions
• “Analysis” Script + Interactive Exploration
  • Static copy of what you did (reproducability)
  • Try things out interactively, then add to your script

R Uses Functions, in Packages

• R revolves around functions
  • Commands that take input, performs computations, and returns results
  • When you download R, it has a “base” set of functions/packages (base R)
• Functions are enclosed in packages
  • These written by R users/developers (like us) - some are bad
  • Think of them as “R Extensions”

Using Packages

• You need to know base R - answers on Google commonly use it
• We will show you some newer and more intuitive ways to do things, not in base R
• RStudio (the company) makes a lot of great packages
• Hadley Wickham writes a lot of them (Employee and Developer at RStudio)
  • TidyVerse (tidyr, readr, ggplot2)
  • An authority on all things R
  • How to trust an R package: http://simplystatistics.org/2015/11/06/how-i-decide-when-to-trust-an-r-package/

RStudio (the software)

RStudio is an Integrated Development Environment (IDE) for R

• It helps the user effectively use R.
• Makes things easier
  
• Is NOT a Graphical User Interface–i.e. no dropdown menus for picking statistical tools (such as Stata)
  • Those do exist R: see Rcmdr or Radiant
• All snapshots in these slides are taken from http://ayeimanol-r.net/2013/04/21/289/

RStudio

Easier working with R

• Syntax highlighting, code completion, and smart indentation
• Keyboard shortcuts
• Easily manage multiple working directories and projects

More information

• Workspace browser and data viewer
• Plot history, zooming, and flexible image and PDF export
• Integrated R help and documentation
• Searchable command history

RStudio/R Console

RStudio/R Console

• Where code is executed (where things happen)
• You can type here for things interactively
• Code is not saved on your disk

RStudio Layout

If RStudio doesn’t look like this (or our RStudio), then do:

RStudio –> Preferences –> Pane Layout

You can also change the Color theme in preferences.

Source/Editor

Source

• Where files open to
• Have R code and comments in them
• Can highlight and press (CMD+Enter (Mac) or Ctrl+Enter (Windows)) to run the code

In a .R file (we call a script), code is saved on your disk

Workspace/Environment

Workspace/Environment

• Tells you what objects are in R
• What exists in memory/what is loaded?/what did I read in?

History

• Shows previous commands. Good to look at for debugging, but don’t rely on it as a script. Make a script!
• Also type the “up” key in the Console to scroll through previous commands

Other Panes

• Files - shows the files on your computer of the directory you are working in
• Viewer - can view data or R objects
• Help - shows help of R commands
• Plots - pretty pictures
• Packages - list of R packages that are loaded in memory

Useful R Studio Shortcuts

• Ctrl + Enter (Cmd + Enter on OS X) in your script evaluates that line of code
  • It’s like copying and pasting the code into the console for it to run.
• Ctrl+1 takes you to the script page
• Ctrl+2 takes you to the console
• http://www.rstudio.com/ide/docs/using/keyboard_shortcuts

Website

EPID 7500 Course Website

John Muschelli’s Course at Johns Hopkins & github repository