Refector the polars type engine to use LazyFrames, add support for Ne…

…sted types (#1526) * refactor polars type engine for LazyFrames, add nested types Signed-off-by: cosmicBboy <niels.bantilan@gmail.com> * add polars engine in the container/component backends Signed-off-by: cosmicBboy <niels.bantilan@gmail.com> * add tests and docs for nested types Signed-off-by: cosmicBboy <niels.bantilan@gmail.com> * fix mypy Signed-off-by: cosmicBboy <niels.bantilan@gmail.com> * fix pylint, mypy Signed-off-by: cosmicBboy <niels.bantilan@gmail.com> * handle annotated types Signed-off-by: cosmicBboy <niels.bantilan@gmail.com> * update docs Signed-off-by: cosmicBboy <niels.bantilan@gmail.com> * update nested dtype docstrings Signed-off-by: cosmicBboy <niels.bantilan@gmail.com> --------- Signed-off-by: cosmicBboy <niels.bantilan@gmail.com>
unionai-oss · Mar 15, 2024 · 7d1b1ba · 7d1b1ba
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diff --git a/docs/source/conf.py b/docs/source/conf.py
@@ -199,7 +199,7 @@
 
 # this is a workaround to filter out forward reference issue in
 # sphinx_autodoc_typehints
-class FilterPandasTypeAnnotationWarning(pylogging.Filter):
+class FilterTypeAnnotationWarnings(pylogging.Filter):
     def filter(self, record: pylogging.LogRecord) -> bool:
         # You probably should make this check more specific by checking
         # that dataclass name is in the message, so that you don't filter out
@@ -225,7 +225,7 @@ def filter(self, record: pylogging.LogRecord) -> bool:
 
 
 logging.getLogger("sphinx_autodoc_typehints").logger.addFilter(
-    FilterPandasTypeAnnotationWarning()
+    FilterTypeAnnotationWarnings()
 )
 
 

diff --git a/docs/source/polars.rst b/docs/source/polars.rst
@@ -322,10 +322,10 @@ present in the data.
 Supported Data Types
 --------------------
 
-``pandera`` currently supports all the `scalar data types <https://docs.pola.rs/py-polars/html/reference/datatypes.html>`__.
-`Nested data types <https://docs.pola.rs/py-polars/html/reference/datatypes.html#nested>`__
-are not yet supported. Built-in python types like ``str``, ``int``, ``float``,
-and ``bool`` will be handled in the same way that ``polars`` handles them:
+``pandera`` currently supports all of the
+`polars data types <https://docs.pola.rs/py-polars/html/reference/datatypes.html>`__.
+Built-in python types like ``str``, ``int``, ``float``, and ``bool`` will be
+handled in the same way that ``polars`` handles them:
 
 .. testcode:: polars
 
@@ -351,6 +351,49 @@ So the following schemas are equivalent:
 
     assert schema1 == schema2
 
+Nested Types
+^^^^^^^^^^^^
+
+Polars nested datetypes are also supported via :ref:`parameterized data types <parameterized dtypes>`.
+See the examples below for the different ways to specify this through the
+object-based and class-based APIs:
+
+.. tabbed:: DataFrameSchema
+
+   .. testcode:: polars
+
+        schema = pa.DataFrameSchema(
+            {
+                "list_col": pa.Column(pl.List(pl.Int64())),
+                "array_col": pa.Column(pl.Array(pl.Int64(), 3)),
+                "struct_col": pa.Column(pl.Struct({"a": pl.Utf8(), "b": pl.Float64()})),
+            },
+        )
+
+.. tabbed:: DataFrameModel (Annotated)
+
+   .. testcode:: polars
+
+        try:
+            from typing import Annotated  # python 3.9+
+        except ImportError:
+            from typing_extensions import Annotated
+
+        class ModelWithAnnotated(pa.DataFrameModel):
+            list_col: Annotated[pl.List, pl.Int64()]
+            array_col: Annotated[pl.Array, pl.Int64(), 3]
+            struct_col: Annotated[pl.Struct, {"a": pl.Utf8(), "b": pl.Float64()}]
+
+.. tabbed:: DataFrameModel (Field)
+
+   .. testcode:: polars
+
+        class ModelWithDtypeKwargs(pa.DataFrameModel):
+            list_col: pl.List = pa.Field(dtype_kwargs={"inner": pl.Int64()})
+            array_col: pl.Array = pa.Field(dtype_kwargs={"inner": pl.Int64(), "width": 3})
+            struct_col: pl.Struct = pa.Field(dtype_kwargs={"fields": {"a": pl.Utf8(), "b": pl.Float64()}})
+
+
 Custom checks
 -------------
 

diff --git a/docs/source/reference/dtypes.rst b/docs/source/reference/dtypes.rst
@@ -92,6 +92,41 @@ Pydantic Dtypes
 
    pandera.engines.pandas_engine.PydanticModel
 
+Polars Dtypes
+-------------
+
+*new in 0.19.0*
+
+.. autosummary::
+   :toctree: generated
+   :template: dtype.rst
+   :nosignatures:
+
+   pandera.engines.polars_engine.Int8
+   pandera.engines.polars_engine.Int16
+   pandera.engines.polars_engine.Int32
+   pandera.engines.polars_engine.Int64
+   pandera.engines.polars_engine.UInt8
+   pandera.engines.polars_engine.UInt16
+   pandera.engines.polars_engine.UInt32
+   pandera.engines.polars_engine.UInt64
+   pandera.engines.polars_engine.Float32
+   pandera.engines.polars_engine.Float64
+   pandera.engines.polars_engine.Decimal
+   pandera.engines.polars_engine.Date
+   pandera.engines.polars_engine.DateTime
+   pandera.engines.polars_engine.Time
+   pandera.engines.polars_engine.Timedelta
+   pandera.engines.polars_engine.Array
+   pandera.engines.polars_engine.List
+   pandera.engines.polars_engine.Struct
+   pandera.engines.polars_engine.Bool
+   pandera.engines.polars_engine.String
+   pandera.engines.polars_engine.Categorical
+   pandera.engines.polars_engine.Category
+   pandera.engines.polars_engine.Null
+   pandera.engines.polars_engine.Object
+
 
 Utility functions
 -----------------

diff --git a/pandera/api/pandas/model.py b/pandera/api/pandas/model.py
@@ -95,7 +95,8 @@ def _build_columns_index(  # pylint:disable=too-many-locals
             dtype = None if dtype is Any else dtype
 
             if (
-                annotation.origin is None
+                annotation.is_annotated_type
+                or annotation.origin is None
                 or annotation.origin in SERIES_TYPES
                 or annotation.raw_annotation in SERIES_TYPES
             ):

diff --git a/pandera/api/polars/model.py b/pandera/api/polars/model.py
@@ -68,7 +68,9 @@ def _build_columns(  # pylint:disable=too-many-locals
 
             dtype = None if dtype is Any else dtype
 
-            if annotation.origin is None:
+            if annotation.origin is None or isinstance(
+                annotation.origin, pl.datatypes.DataTypeClass
+            ):
                 if check_name is False:
                     raise SchemaInitError(
                         f"'check_name' is not supported for {field_name}."

diff --git a/pandera/backends/polars/components.py b/pandera/backends/polars/components.py
@@ -11,6 +11,7 @@
 from pandera.backends.polars.base import PolarsSchemaBackend, is_float_dtype
 from pandera.config import ValidationScope
 from pandera.errors import (
+    ParserError,
     SchemaDefinitionError,
     SchemaError,
     SchemaErrors,
@@ -153,12 +154,8 @@ def coerce_dtype(
             return check_obj
 
         try:
-            return (
-                check_obj.cast({schema.selector: schema.dtype.type})
-                .collect()
-                .lazy()
-            )
-        except (pl.ComputeError, pl.InvalidOperationError) as exc:
+            return schema.dtype.try_coerce(check_obj)
+        except ParserError as exc:
             raise SchemaError(
                 schema=schema,
                 data=check_obj,
@@ -299,7 +296,7 @@ def check_dtype(
             obj_dtype = check_obj_subset.schema[column]
             results.append(
                 CoreCheckResult(
-                    passed=obj_dtype.is_(schema.dtype.type),
+                    passed=schema.dtype.check(obj_dtype),
                     check=f"dtype('{schema.dtype}')",
                     reason_code=SchemaErrorReason.WRONG_DATATYPE,
                     message=(

diff --git a/pandera/backends/polars/container.py b/pandera/backends/polars/container.py
@@ -8,10 +8,12 @@
 
 from pandera.api.base.error_handler import ErrorHandler
 from pandera.api.polars.container import DataFrameSchema
+from pandera.api.polars.types import PolarsData
 from pandera.backends.base import CoreCheckResult, ColumnInfo
 from pandera.backends.polars.base import PolarsSchemaBackend
 from pandera.config import ValidationScope
 from pandera.errors import (
+    ParserError,
     SchemaError,
     SchemaErrors,
     SchemaErrorReason,
@@ -388,16 +390,15 @@ def _coerce_dtype_helper(
         """
         error_handler = ErrorHandler(lazy=True)
 
-        if schema.dtype is not None:
-            obj = obj.cast(schema.dtype.type)
-        else:
-            obj = obj.cast(
-                {k: v.dtype.type for k, v in schema.columns.items()}
-            )
-
         try:
-            obj = obj.collect().lazy()
-        except pl.exceptions.ComputeError as exc:
+            if schema.dtype is not None:
+                obj = schema.dtype.try_coerce(obj)
+            else:
+                for col_schema in schema.columns.values():
+                    obj = col_schema.dtype.try_coerce(
+                        PolarsData(obj, col_schema.selector)
+                    )
+        except (ParserError, pl.ComputeError) as exc:
             error_handler.collect_error(
                 validation_type(SchemaErrorReason.DATATYPE_COERCION),
                 SchemaErrorReason.DATATYPE_COERCION,

diff --git a/pandera/dtypes.py b/pandera/dtypes.py
@@ -413,7 +413,7 @@ class Decimal(_Number):
     """The number of digits after the decimal point."""
 
     # pylint: disable=line-too-long
-    rounding: str = dataclasses.field(
+    rounding: Optional[str] = dataclasses.field(
         default_factory=lambda: decimal.getcontext().rounding
     )
     """

diff --git a/pandera/engines/__init__.py b/pandera/engines/__init__.py
@@ -1,6 +1,14 @@
 """Pandera type engines."""
 
-from pandera.engines.utils import pydantic_version
+import pydantic
+
+from packaging import version
+
+
+def pydantic_version():
+    """Return the pydantic version."""
+
+    return version.parse(pydantic.__version__)
 
 
 PYDANTIC_V2 = pydantic_version().release >= (2, 0, 0)