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Comparison with Existing Solutions

Feature Matrix

Feature Colnade Pandera StaticFrame Patito Narwhals
Column refs checked statically ✅ ❌ ❌ ❌ ❌
Schema preserved through ops ✅ Nominal only ❌ ❌ ❌
Works with existing engines ✅ ✅ ❌ Polars only ✅
No plugins or code gen ✅ ❌ (mypy plugin) ✅ ✅ ✅
Generic utility functions ✅ ❌ ❌ ❌ ❌
Struct/List typed access ✅ ❌ ❌ ❌ ❌
Lazy execution support ✅ ❌ ❌ ❌ ✅

Detailed Comparisons

Pandera

Pandera provides runtime schema validation with a mypy plugin for basic static checking. However, its static checking is nominal only — it verifies that DataFrame[A] is passed where DataFrame[A] is expected, but cannot verify that the dataframe's contents match after transformation. Column references within function bodies remain unchecked strings.

Colnade's advantage: Column references are class attributes (Users.age not "age"), so misspellings are caught at lint time. Schema types track through all operations, not just at function boundaries.

StaticFrame

StaticFrame uses PEP 646 TypeVarTuple to encode column types as variadic generic parameters. Column types are positional, not named — there's no way to express "has a column called age of type UInt8." Schema transformations aren't tracked, and it requires adopting a niche DataFrame engine.

Colnade's advantage: Named columns with full type information. Works with existing engines (Polars, with more coming). Schema transformations are tracked through cast_schema.

Patito

Patito provides Pydantic-style model classes that serve as Polars DataFrame schemas, with runtime validation. Clean API design, but purely runtime validation — pl.col("misspelled") passes the type checker.

Colnade's advantage: Static checking of all column references, not just runtime validation. Same schema-as-model pattern, but with compile-time safety.

Narwhals

Narwhals is a lightweight compatibility layer providing a Polars-like API across multiple backends. It solves "write once, run on any engine" but provides no schema typing or static safety.

Colnade's advantage: Full static type safety for column references and schema transformations. Colnade complements the cross-engine approach rather than competing with it.