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.
本练习是课程的一部分
Data Transformation with Polars
练习说明
- Add a column
cumulative_rentalswith the cumulative sum ofrentals.
交互式实操练习
通过完成这段示例代码来试试这个练习。
# Add a cumulative sum of rentals
bikes.with_columns(
pl.col("rentals").____().alias("____")
)