Introduction to Paths

• To use data stored on a computer we need to tell R where it is
• This is done using paths
• Go to data page and download shrub dimensions data to a datacarp directory
• Paths can be absolute

'/home/ethan/datacarp/shrub-dimensions-labeled.csv' # OSX/Linux
'/Users/ethan/datacarp/shrub-dimensions-labeled.csv' # Windows

• Folders/Directories are separate by / with the file name at the end

• Include the file extension (the part after the .)

• Paths can also be relative

'datacarp/shrub-dimensions-labeled.csv'

• “From where I am the shrub-dimensions file is in the Desktop subdirectory”
• Absolute & relative paths are the same if R thinks it’s in /home/ethan/

Find out where you are

• To find out where R is use getwd()

getwd()

• “get working directory”
• The “working directory” is where the program starts from

Loading data

• For data in the working directory just use the file name

shrub_data <- read.csv('shrub-dimensions-labeled.csv')

• Download a file into working directory using download.file()

• For data not in the working directory - two options
  • tell R where it is
  • change the working directory to where it is
• Changing the working directory is common
  • Who here uses setwd regularly?
  • Does that ever cause any issues?
    • Working on a different computer?
    • Working with someone else’s files?
• Have working directory automatically set to a common place and use relative paths

Projects

• Think of each project as a self-contained unit in a single folder/directory
• Treat all locations as relative to that single directory
• To do this in RStudio we use projects
• File -> New Project -> New Directory -> New Project -> datacarp
• Or use Existing Directory to choose an existing directory
• Creates .Rproj file
  • Isn’t project itself
  • Contains project info
  • Don’t change manually
• Can switch between projects using File -> Recent Projects or Open Project
• Keeps track the state of RStudio when you last worked with that project

• Create a project for this assignment
• Do Exercise 9 - Shrub Volume Data Frame.

Assignments

• This idea of projects as folders is also important for how we share code
• To turn in assignments you will submit a compressed version of the folder for that assignment
• Demo compressing a folder
• Version control also treats projects as folders

Assign remaining exercises. Submit as compressed main folder, see Assignment Submission & Checklist