Week 7: Data Transformation

Today’s Question

How do data verbs become a language for answering questions?

Core Verbs

• filter() keeps rows.
• select() keeps columns.
• mutate() creates variables.
• group_by() defines groups.
• summarize() reduces rows.

R Pattern

mtcars |>
  group_by(cyl) |>
  summarize(mean_mpg = mean(mpg), .groups = "drop")

Validation

After a transformation, check row counts, column names, groups, and units.

AI Check

Generated pipelines often answer a nearby question. Check the exact question.