Calculating the difference from hourly mean

Totals are useful, but deviations tell a richer story. Calculate how much each hour's rentals differ from the average for that hour across all days to quickly flag above-normal or below-normal demand.

polars is loaded as pl. The DataFrame bikes is available with columns time, rentals, temp, and hour.

Cet exercice fait partie du cours

<cours>Data Transformation with Polars</cours>

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Instructions de l’exercice

Add a column diff_from_avg showing rentals minus the hourly mean of rentals.

Exercice interactif pratique

Essayez cet exercice en complétant ce code d’exemple.

# Calculate how each rental differs from its hourly average
bikes.with_columns(
    (pl.col("rentals") - pl.col("rentals").____().over("____")).alias("____")
)

Modifier et exécuter le code