Overriding the inferred schema

When Polars scans the vendor export, it uses the first few rows to infer column types. The branch_code column uses 3-digit identifiers with leading zeros ("001", "002", …), but Polars sees integers and parses them as Int64, silently dropping the zeros. Override the schema so branch_code stays a string.

The inferred schema is already printed for you, so you can see what Polars guessed without any overrides.

Latihan ini merupakan bagian dari kursus

Scaling and Optimizing Data Pipelines with Polars

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Instruksi latihan

Override branch_code so it's read as pl.String.

Latihan interaktif langsung praktik

Cobalah latihan ini dengan melengkapi kode contoh ini.

schema = pl.scan_csv(
    MESSY_CSV_PATH,
    separator=";",
    skip_rows=2,
    infer_schema_length=5,
    # Force branch_code to String
    schema_overrides={"____": pl.____},
).collect_schema()

print("\nOverridden schema:")
print(schema)

Edit dan Jalankan Kode