polars.ScanCastOptions#

class polars.ScanCastOptions(
*,
integer_cast: Literal['upcast', 'forbid'] = 'forbid',
float_cast: Literal['forbid'] | FloatCastOption | Collection[FloatCastOption] = 'forbid',
datetime_cast: Literal['forbid'] | DatetimeCastOption | Collection[DatetimeCastOption] = 'forbid',
missing_struct_fields: Literal['insert', 'raise'] = 'raise',
extra_struct_fields: Literal['ignore', 'raise'] = 'raise',
_internal_call: bool = False,
)[source]#

Options for scanning files.

__init__(
*,
integer_cast: Literal['upcast', 'forbid'] = 'forbid',
float_cast: Literal['forbid'] | FloatCastOption | Collection[FloatCastOption] = 'forbid',
datetime_cast: Literal['forbid'] | DatetimeCastOption | Collection[DatetimeCastOption] = 'forbid',
missing_struct_fields: Literal['insert', 'raise'] = 'raise',
extra_struct_fields: Literal['ignore', 'raise'] = 'raise',
_internal_call: bool = False,
) → None[source]#

Common configuration for scanning files.

Warning

This functionality is considered unstable. It may be changed at any point without it being considered a breaking change.

Parameters:
integer_cast

Configuration for casting from integer types:

  • upcast: Allow lossless casting to wider integer types.

  • forbid: Raises an error if dtypes do not match.

float_cast

Configuration for casting from float types:

  • upcast: Allow casting to higher precision float types.

  • downcast: Allow casting to lower precision float types.

  • forbid: Raises an error if dtypes do not match.

datetime_cast

Configuration for casting from datetime types:

  • nanosecond-downcast: Allow nanosecond precision datetime to be downcasted to any lower precision. This has a similar effect to PyArrow’s coerce_int96_timestamp_unit.

  • convert-timezone: Allow casting to a different timezone.

  • forbid: Raises an error if dtypes do not match.

missing_struct_fields

Configuration for behavior when struct fields defined in the schema are missing from the data:

  • insert: Inserts the missing fields.

  • raise: Raises an error.

extra_struct_fields

Configuration for behavior when extra struct fields outside of the defined schema are encountered in the data:

  • ignore: Silently ignores.

  • raise: Raises an error.

Methods

__init__(*[, integer_cast, float_cast, ...])

Common configuration for scanning files.