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.
Deze oefening maakt deel uit van de cursus
Data Transformation with Polars
Oefeninstructies
- Add a column
cumulative_rentalswith the cumulative sum ofrentals.
Interactieve oefening met praktijkervaring
Probeer deze oefening door deze voorbeeldcode aan te vullen.
# Add a cumulative sum of rentals
bikes.with_columns(
pl.col("rentals").____().alias("____")
)