Intro to Practical Computing

Practical Computing and Data Science Tools

Agenda

• Review
• Naming best practices
• Files and directories

Last week

• Syllabus
• Lab 1
• Tools for the course: R, RStudio, and Quarto

Syllabus

• Recall lecture tickets are due in person at the beginning of lecture.
  
• Course late policy has been added to online version.
• Let’s quickly review the late policy.

www.for128.org/syllabus.html

Lab 1

• If you’re having troubles, technical or otherwise, come to office hours.
• Make sure to turn in (.pdf and .qmd) to D2L by 5pm on Wednesday (tomorrow).

Data Science Tools

• R is a programming language.
• RStudio is an IDE (what we use to interact with R and our computer).
• Quarto is a markdown language, for writing reports.

• You, the chef

• R, the ingredients

• RStudio, your kitchen

• Quarto, the plated final product

Practical computing

Practical computing

• Understanding your computer and its file system is vital to success in this class and beyond.

• Last week, we threw you into the deep end with data science tools.

• This week, we’ll spend a bit more time on the details to help you interact with your computer and these tools.

• Today, we’ll focus on file systems and file/folder naming.

Naming files and folders

Some best practices are important for naming files and folders:

• Use consistent casing:
  • delimiter naming, e.g. lab_01.qmd or cat_pictures
  • camel case, e.g., finalProjectMaterials.qmd or catPictures
• Name your files and folders clearly, concisely, and informatively:
  • Good: for128_f24
  • Bad: my_work_for_forestry128_in_fall_2024
  • Really bad: myWorkFor_forestry128_inFall_2024

File systems / directories

• Every time you create or download a file, you are storing it somewhere in your computer’s file system.
• But where? 🤔

File systems / directories

• Think of your computer’s file system as a tree

The root

The root directory is the start or base of your file system.

• On Windows, the root is C:/
• On macOS and Linux, the root is /

Your home directory

When interacting with your computer, you are logged in as a user. Each user has a home directory.

For example:

• On Windows, C:/Users/Sarah
• On macOS and Linux, /home/sarah

Your home directory

It is often easier to use a shortcut to access your home directory: ~. On Windows, macOS, and Linux, you can use ~ to access your home directory:

• ~ is equivalent to C:/Users/Sarah and /home/sarah

Paths

C:/Users/Sarah and /home/sarah are examples of paths. In particular, these are paths to Sarah’s home directory.

Paths

• Paths specify the location of a file or folder on your computer, let’s look at a few examples:
  • /
  • /home/sarah
  • /home/sarah/Desktop
  • /home/sarah/Documents/for128/lab_01.qmd
  • ~/Documents/for128/lab_01.qmd

Paths

• Equivalent paths, on Windows:
  • C:/
  • C:/Users/Sarah
  • C:/Users/Sarah/Desktop
  • C:/Users/Sarah/Documents/for128/lab_01.qmd
  • ~/Documents/for128/lab_01.qmd

Relative vs. absolute paths

• So far, we’ve only shown absolute paths.
• Absolute paths show a file or folder in reference to your computer’s file system.
• Relative paths, on the other hand, show a file or folder in relation to a working directory.

Working directory example

• Recall the absolute path to lab_01.qmd:
  • /home/sarah/Documents/for128/lab_01.qmd
• Say our working directory is the documents folder:
  • /home/sarah/Documents
• Then the relative path to lab_01.qmd is:
  • for128/lab_01.qmd

Use relative (not absolute) paths!

Why?

• Reproducibility!
  • They will work on any computer, not just your own.
• Clear and concise.
• But really, reproducibility.

Working directories in Quarto and R demo

What have we learned?

• In Quarto, the default working directory is the folder where the quarto document lives.
  • Crucial note: this may be different than the working directory in your R console.
• You can set your working directory in R with setwd()
  • Just for your R console, though. This does not apply to Quarto documents.
• You can get your current working directory in R with getwd()

Next time

• Remember, lab 1 is due tomorrow at 5pm on D2L.
• RStudio projects.
• Reading and writing data.