Importing and recoding data

Lecture 9

Dr. Benjamin Soltoff

Cornell University
INFO 2951 - Spring 2025

February 20, 2025

Announcements

Announcements

• Lab 03
• Homework 03
• Project proposal

Update your renv.lock file

1. To install a new package for the project, use renv::install() or install.packages().
2. Run renv::snapshot(type = "all"). This will update renv.lock to include all packages used in the project library.
3. Stage, commit, and push the renv.lock file.

Tip

More tips and resources for your team projects.

Data “wrangling”

Reading data into R

• Local data files
• Databases
• Web scraping
• Application programming interfaces (APIs)

Reading rectangular data

• {readr}:
  • Most commonly: read_csv()
  • Maybe also: read_tsv(), read_delim(), etc.
• {readxl}: read_excel()
• {arrow}: read_arrow(), read_parquet()
• {haven}: read_sas(), read_sav(), read_dta()
• {googlesheets4}: read_sheet()
• {data.table}: fread()¹

Avoid read.csv(), read.tsv(), etc. (base R functions)

1. When speed is of the essence

Application exercise

Powerball Lottery

Powerball Lottery

Powerball Lottery

ae-07

Instructions

• Go to the course GitHub org and find your ae-07 (repo name will be suffixed with your GitHub name).
• Clone the repo in RStudio, run renv::restore() to install the required packages, open the Quarto document in the repo, and follow along and complete the exercises.
• Render, commit, and push your edits by the AE deadline – end of the day

Wrap up

Recap

• Simplify your life – get the data in as simple a format as possible
• Examine the file’s structure before attempting to import into R. Use the RStudio interactive menu as necessary.
• Ensure all data cleaning is reproducible. Do not replace your raw data files.

Jazz or Not Jazz?