Narwhals Backend¶

new in 0.32.0

Opt-in Narwhals-powered validation backend that powers the Polars, Ibis, and PySpark SQL integrations behind a single unified code path. Requires the narwhals extra. See Narwhals-powered backends for the user-facing guide.

Data Objects¶

Objects passed to custom check functions when the Narwhals backend is active.

`pandera.api.narwhals.types.NarwhalsData`	Data container for Narwhals-backed validation.
`pandera.api.narwhals.types.NarwhalsCheckResult`	Check result for user-defined checks on Narwhals frames.

Backends¶

`pandera.backends.narwhals.base.NarwhalsSchemaBackend`	Base schema backend for Narwhals-backed DataFrames.
`pandera.backends.narwhals.container.DataFrameSchemaBackend`
`pandera.backends.narwhals.components.ColumnBackend`	Per-column validation backend for Narwhals-backed DataFrames.
`pandera.backends.narwhals.checks.NarwhalsCheckBackend`	Check backend for Narwhals.

Narwhals Dtypes¶

`pandera.engines.narwhals_engine.DataType`	Base `DataType` for boxing Narwhals data types.
`pandera.engines.narwhals_engine.Int8`	Narwhals signed 8-bit integer data type.
`pandera.engines.narwhals_engine.Int16`	Narwhals signed 16-bit integer data type.
`pandera.engines.narwhals_engine.Int32`	Narwhals signed 32-bit integer data type.
`pandera.engines.narwhals_engine.Int64`	Narwhals signed 64-bit integer data type.
`pandera.engines.narwhals_engine.UInt8`	Narwhals unsigned 8-bit integer data type.
`pandera.engines.narwhals_engine.UInt16`	Narwhals unsigned 16-bit integer data type.
`pandera.engines.narwhals_engine.UInt32`	Narwhals unsigned 32-bit integer data type.
`pandera.engines.narwhals_engine.UInt64`	Narwhals unsigned 64-bit integer data type.
`pandera.engines.narwhals_engine.Float32`	Narwhals 32-bit floating point data type.
`pandera.engines.narwhals_engine.Float64`	Narwhals 64-bit floating point data type.
`pandera.engines.narwhals_engine.String`	Narwhals string data type.
`pandera.engines.narwhals_engine.Bool`	Narwhals boolean data type.
`pandera.engines.narwhals_engine.Date`	Narwhals date data type.
`pandera.engines.narwhals_engine.DateTime`	Narwhals datetime data type.
`pandera.engines.narwhals_engine.Duration`	Narwhals duration data type.
`pandera.engines.narwhals_engine.Categorical`	Narwhals categorical data type.
`pandera.engines.narwhals_engine.List`	Narwhals List nested type.
`pandera.engines.narwhals_engine.Struct`	Narwhals Struct nested type.

Engine¶

pandera.engines.narwhals_engine.Engine

Narwhals data type engine.

Built-in Check Expressions¶

Narwhals expression implementations of the built-in checks, shared by the Polars, Ibis, and PySpark SQL integrations when the Narwhals backend is enabled.

`pandera.backends.narwhals.builtin_checks.equal_to`	Ensure all elements of a column equal a certain value.
`pandera.backends.narwhals.builtin_checks.not_equal_to`	Ensure no element of a column equals a certain value.
`pandera.backends.narwhals.builtin_checks.greater_than`	Ensure values of a column are strictly greater than a minimum value.
`pandera.backends.narwhals.builtin_checks.greater_than_or_equal_to`	Ensure all values are greater than or equal to a minimum value.
`pandera.backends.narwhals.builtin_checks.less_than`	Ensure values of a column are strictly less than a maximum value.
`pandera.backends.narwhals.builtin_checks.less_than_or_equal_to`	Ensure all values are less than or equal to a maximum value.
`pandera.backends.narwhals.builtin_checks.in_range`	Ensure all values of a series are within an interval.
`pandera.backends.narwhals.builtin_checks.isin`	Ensure only allowed values occur within a series.
`pandera.backends.narwhals.builtin_checks.notin`	Ensure some defined values don't occur within a series.
`pandera.backends.narwhals.builtin_checks.str_matches`	Ensure that all values start with a match of a regular expression pattern.
`pandera.backends.narwhals.builtin_checks.str_contains`	Ensure that a pattern can be found within each row.
`pandera.backends.narwhals.builtin_checks.str_startswith`	Ensure that all values start with a certain string.
`pandera.backends.narwhals.builtin_checks.str_endswith`	Ensure that all values end with a certain string.
`pandera.backends.narwhals.builtin_checks.str_length`	Ensure that the length of strings is within a specified range.