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.

Bu egzersiz, kursun bir parçasıdır

Scaling and Optimizing Data Pipelines with Polars

Kursa Göz Atın

Egzersiz talimatları

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

Uygulamalı etkileşimli egzersiz

Bu egzersizi bu örnek kodu tamamlayarak deneyin.

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)

Kodu Düzenle ve Çalıştır