JonasJ-ap commented on code in PR #6997:
URL: https://github.com/apache/iceberg/pull/6997#discussion_r1133368841
##########
python/pyiceberg/io/pyarrow.py:
##########
@@ -484,6 +495,203 @@ def expression_to_pyarrow(expr: BooleanExpression) ->
pc.Expression:
return boolean_expression_visit(expr, _ConvertToArrowExpression())
+def pyarrow_to_schema(schema: pa.Schema) -> Schema:
+ visitor = _ConvertToIceberg()
+ struct_results: List[Optional[IcebergType]] = []
+ for field in schema:
+ visitor.before_field(field)
+ struct_result = visit_pyarrow(field.type, visitor)
+ visitor.after_field(field)
+ struct_results.append(struct_result)
+ return visitor.schema(schema, struct_results)
+
+
+@singledispatch
+def visit_pyarrow(obj: pa.DataType, visitor: PyArrowSchemaVisitor[T]) -> T:
+ """A generic function for applying a pyarrow schema visitor to any point
within a schema
+
+ The function traverses the schema in post-order fashion
+
+ Args:
+ obj(pa.DataType): An instance of a Schema or an IcebergType
+ visitor (PyArrowSchemaVisitor[T]): An instance of an implementation of
the generic PyarrowSchemaVisitor base class
+
+ Raises:
+ NotImplementedError: If attempting to visit an unrecognized object type
+ """
+ raise NotImplementedError("Cannot visit non-type: %s" % obj)
+
+
+@visit_pyarrow.register(pa.StructType)
+def _(obj: pa.StructType, visitor: PyArrowSchemaVisitor[T]) -> T:
+ struct_results: List[Optional[T]] = []
+ for field in obj:
+ visitor.before_field(field)
+ struct_result = visit_pyarrow(field.type, visitor)
+ visitor.after_field(field)
+ struct_results.append(struct_result)
+
+ return visitor.struct(obj, struct_results)
+
+
+@visit_pyarrow.register(pa.ListType)
+def _(obj: pa.ListType, visitor: PyArrowSchemaVisitor[T]) -> Optional[T]:
+ visitor.before_list_element(obj.value_field)
+ list_result = visit_pyarrow(obj.value_field.type, visitor)
+ visitor.after_list_element(obj.value_field)
+ return visitor.list(obj, list_result)
+
+
+@visit_pyarrow.register(pa.MapType)
+def _(obj: pa.MapType, visitor: PyArrowSchemaVisitor[T]) -> Optional[T]:
+ visitor.before_map_key(obj.key_field)
+ key_result = visit_pyarrow(obj.key_field.type, visitor)
+ visitor.after_map_key(obj.key_field)
+ visitor.before_map_value(obj.item_field)
+ value_result = visit_pyarrow(obj.item_field.type, visitor)
+ visitor.after_map_value(obj.item_field)
+ return visitor.map(obj, key_result, value_result)
+
+
+@visit_pyarrow.register(pa.DataType)
+def _(obj: pa.DataType, visitor: PyArrowSchemaVisitor[T]) -> T:
+ if pa.types.is_nested(obj):
+ raise TypeError(f"Expected primitive type, got {type(obj)}")
+ return visitor.primitive(obj)
+
+
+class PyArrowSchemaVisitor(Generic[T], ABC):
Review Comment:
Thank you for your suggestion. I think you mean the `_ConvertToIceberg`
class downwards which is a conrete implementation of the abstract class
`PyArrowSchemaVisitor`. So I removed `ABC` from `_ConvertToIceberg` class:
```Python
class _ConvertToIceberg(PyArrowSchemaVisitor[IcebergType]):
```
##########
python/pyiceberg/io/pyarrow.py:
##########
@@ -484,6 +495,203 @@ def expression_to_pyarrow(expr: BooleanExpression) ->
pc.Expression:
return boolean_expression_visit(expr, _ConvertToArrowExpression())
+def pyarrow_to_schema(schema: pa.Schema) -> Schema:
+ visitor = _ConvertToIceberg()
+ struct_results: List[Optional[IcebergType]] = []
+ for field in schema:
+ visitor.before_field(field)
+ struct_result = visit_pyarrow(field.type, visitor)
+ visitor.after_field(field)
+ struct_results.append(struct_result)
+ return visitor.schema(schema, struct_results)
+
+
+@singledispatch
+def visit_pyarrow(obj: pa.DataType, visitor: PyArrowSchemaVisitor[T]) -> T:
+ """A generic function for applying a pyarrow schema visitor to any point
within a schema
+
+ The function traverses the schema in post-order fashion
+
+ Args:
+ obj(pa.DataType): An instance of a Schema or an IcebergType
+ visitor (PyArrowSchemaVisitor[T]): An instance of an implementation of
the generic PyarrowSchemaVisitor base class
+
+ Raises:
+ NotImplementedError: If attempting to visit an unrecognized object type
+ """
+ raise NotImplementedError("Cannot visit non-type: %s" % obj)
+
+
+@visit_pyarrow.register(pa.StructType)
+def _(obj: pa.StructType, visitor: PyArrowSchemaVisitor[T]) -> T:
+ struct_results: List[Optional[T]] = []
+ for field in obj:
+ visitor.before_field(field)
+ struct_result = visit_pyarrow(field.type, visitor)
+ visitor.after_field(field)
+ struct_results.append(struct_result)
+
+ return visitor.struct(obj, struct_results)
+
+
+@visit_pyarrow.register(pa.ListType)
+def _(obj: pa.ListType, visitor: PyArrowSchemaVisitor[T]) -> Optional[T]:
+ visitor.before_list_element(obj.value_field)
+ list_result = visit_pyarrow(obj.value_field.type, visitor)
+ visitor.after_list_element(obj.value_field)
+ return visitor.list(obj, list_result)
+
+
+@visit_pyarrow.register(pa.MapType)
+def _(obj: pa.MapType, visitor: PyArrowSchemaVisitor[T]) -> Optional[T]:
+ visitor.before_map_key(obj.key_field)
+ key_result = visit_pyarrow(obj.key_field.type, visitor)
+ visitor.after_map_key(obj.key_field)
+ visitor.before_map_value(obj.item_field)
+ value_result = visit_pyarrow(obj.item_field.type, visitor)
+ visitor.after_map_value(obj.item_field)
+ return visitor.map(obj, key_result, value_result)
+
+
+@visit_pyarrow.register(pa.DataType)
+def _(obj: pa.DataType, visitor: PyArrowSchemaVisitor[T]) -> T:
+ if pa.types.is_nested(obj):
+ raise TypeError(f"Expected primitive type, got {type(obj)}")
+ return visitor.primitive(obj)
+
+
+class PyArrowSchemaVisitor(Generic[T], ABC):
Review Comment:
Thank you for your suggestion. I think you mean the `_ConvertToIceberg`
class downwards which is a concrete implementation of the abstract class
`PyArrowSchemaVisitor`. So I removed `ABC` from `_ConvertToIceberg` class:
```Python
class _ConvertToIceberg(PyArrowSchemaVisitor[IcebergType]):
```
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
