Data Transformation II

Week 10, Fall 2025

• Start: Monday, October 27
• End: Friday, October 31

Summary

This week we will continue our discussion of the tidyverse. In particular, we’ll discussion data import and export, tidying data, and joining data.

Learning Objectives

After completing this week, you are expected to be able to:

• Identify “tidy” data.
• Transform untidy data to tidy data using tidyr, in particular:
  • pivot_wider to transform long data to wide data
  • pivot_longer to transform wide data to long data, which is most often tidy
• Import and export data using readr.
• Combine multiple datasets using joins from dplyr.

Reading

Link	Source
Introduction	R4DS
Data Visualization	R4DS
Workflow: Basics	R4DS
Data Transformation	R4DS
Workflow: Code Style	R4DS
Data Tidying	R4DS
Workflow: Scripts and Projects	R4DS
Data Import	R4DS
Workflow: Getting Help	R4DS
Joins	R4DS
Moneyball in R	Instructor Website

Cheatsheets

Link	Source
ggplot2	Posit Cheatsheets
dplyr	Posit Cheatsheets
readr	Posit Cheatsheets
tidyr	Posit Cheatsheets

Data

• Package: Lahman
• Package: nycflights13
• Package: bbd

Video

Title	Link	Mirror
10.1 - Welcome to Week 10	10.1 - YouTube	10.1 - ClassTranscribe
10.2 - Data Transformation: Import, Pivots, and Joins	10.2 - YouTube	10.2 - ClassTranscribe
10.3 - Moneyball in R	10.3 - YouTube	10.3 - ClassTranscribe
10.4 - Lab 07	10.4 - YouTube	10.4 - ClassTranscribe

Assignments

Assignment	Deadline	Credit
Lab 06	Thursday, October 30	100%
Quiz 06	Thursday, October 30	105%
Lab 07	Thursday, November 6	100%
Quiz 07	Thursday, November 6	105%

Office Hours

Professor Eck’s Office Hours are cancelled this week.