Calculating cumulative rentals
Rolling sums smooth short-term noise, but sometimes you need the running total from the very start. Cumulative sums track how usage builds up over time, useful for capacity planning and monthly reporting.
polars is loaded as pl. The DataFrame bikes is available with columns time, rentals, and temp.
Cet exercice fait partie du cours
Data Transformation with Polars
Instructions
- Add a column
cumulative_rentalswith the cumulative sum ofrentals.
Exercice interactif pratique
Essayez cet exercice en complétant cet exemple de code.
# Add a cumulative sum of rentals
bikes.with_columns(
pl.col("rentals").____().alias("____")
)