First Steps in R and RStudio Exercises

This repository holds exercise and solutions files related to the First Steps in R and RStudio Skills Series offered by Arcus Education.

Here is a breakdown of some of the topics covered in each exercise:

Session 2

• Source and Visual buttons in the RStudio IDE
• The green "play" button that executes code chunks in the RStudio IDE
• Loading the tidyverse package using library
• Verbose output that can happen from loading packages
• Loading a library allows you to use its functions
• Using the read_csv function to ingest a csv file
• Working with the Environment tab in the RStudio IDE
  • Blue triangle beside data frames
  • Clicking on the names of data frames
• Good names for objects (variables, columns) in R
• head, tail, summary as ways to examine an object in R
• R often has multiple ways to do the same thing
• Help in R and reading help documentation
• Rendering a Quarto document

Session 3

• Using chunk options like warning=FALSE and message=FALSE
• The grammar of graphics in ggplot2:
  • Start with a tidy data frame
  • Add a geometric representation
  • Add aesthetic mappings
• Working with histogram binwidth "error" message
• You don't necessarily have to pass labels for every argument
• "color" (0-1D) vs "fill" (2D) in ggplot2
• Mapping color vs setting color
• Adding labels using labs
• Using palettes (in particular, scale_color_brewer)
• Specifying exact colors (in particular, scale_fill_manual)
• Using position (stacking vs side-by-side)
• Using alpha (transparency)
• Faceting

Session 4

• Naming code chunks
• Using the code chunk navigator in the RStudio IDE
• Data types in R
• str() to look at data types (mirrored with blue triangle in Environment tab)
• View() to look within data frame (mirrored with clicking name in Environment tab)
• Factors in R
• Using mutate to transform variables to factors (including ordered)
• Using select and filter to subset data

Session 5

• Hands on work!