Extracting a primary genre

You've joined the data team at a streaming movie startup. They store film metadata in a Parquet file where each movie's genres is a list of strings, since most films span several genres. Pull the first listed genre out of each row into a clean top-level primary_genre column.

polars is loaded as pl, and the DataFrame movies is pre-loaded from the Parquet file.

This exercise is part of the course

Scaling and Optimizing Data Pipelines with Polars

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Exercise instructions

Extract the first element from each row's genres list using a list expression.
Alias the new column as primary_genre.

Hands-on interactive exercise

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

result = movies.select(
    "movie_title",
    "genres",
    # Get the first genre
    pl.col("genres").list.____(0).alias("____"),
).head(8)
print(result)

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