Summarizing digital checkouts

The reporting team needs the total number of digital checkouts by material type for this week's summary. Build the entire pipeline lazily and call .collect() only at the very end so Polars can plan the whole query at once.

This exercise is part of the course

Scaling and Optimizing Data Pipelines with Polars

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Exercise instructions

Filter library to rows where use is "Digital".
Group the filtered rows by format.
Trigger execution at the very end of the pipeline.

Hands-on interactive exercise

Have a go at this exercise by completing this sample code.

result = (
    library
    # Filter to digital checkouts
    .filter(pl.col("use") == "____")
    # Group by format
    .group_by("____")
    .agg(pl.col("checkouts").sum().alias("total"))
    .sort("total", descending=True)
    # Trigger execution at the end
    .____()
)
print(result)

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