Matching to the nearest price update

Listing prices change over time, but inquiries arrive at irregular intervals. To analyze pricing accuracy, you want to match each inquiry to the closest price update for that listing - whether it happened before or after the inquiry.

polars is loaded as pl, and the DataFrames inquiries and price_history are available for you, both with name and date columns.

Deze oefening maakt deel uit van de cursus

Data Transformation with Polars

Bekijk cursus

Oefeninstructies

Sort both DataFrames by date before joining.
Use the by parameter to match within each listing using the name column.
Set the strategy to find the closest date in either direction.

Interactieve oefening met praktijkervaring

Probeer deze oefening door deze voorbeeldcode aan te vullen.

# Sort and join on date
matches = inquiries.sort("____").____(
    price_history.sort("____"),
    on="date",
    # Match within each listing
    by="____",
    # Find the closest date
    strategy="____"
)

print(matches)

Code bewerken en uitvoeren