merlin.dag.BaseOperator#

class merlin.dag.BaseOperator[source]#

Bases: object

Base class for all operator classes.

__init__()#

Methods

`__init__`()
`column_mapping`(col_selector)	Compute which output columns depend on which input columns
`compute_column_schema`(col_name, input_schema)
`compute_input_schema`(root_schema, ...)	Given the schemas coming from upstream sources and a column selector for the input columns, returns a set of schemas for the input columns this operator will use
`compute_output_schema`(input_schema, col_selector)	Given a set of schemas and a column selector for the input columns, returns a set of schemas for the transformed columns this operator will produce
`compute_selector`(input_schema, selector[, ...])	Provides a hook method for sub-classes to override to implement custom column selection logic.
`create_node`(selector)
`load_artifacts`([artifact_path])	Load artifacts from disk required for operator function.
`output_column_names`(col_selector)	Given a set of columns names returns the names of the transformed columns this operator will produce
`save_artifacts`([artifact_path])	Save artifacts required to be reload operator state from disk
`transform`(col_selector, transformable)	Transform the dataframe by applying this operator to the set of input columns
`validate_schemas`(parents_schema, ...[, ...])	Provides a hook method that sub-classes can override to implement schema validation logic.

Attributes

`dependencies`	Defines an optional list of column dependencies for this operator.
`dynamic_dtypes`
`is_subgraph`
`label`
`output_dtype`
`output_properties`
`output_tags`
`supported_formats`
`supports`	Returns what kind of data representation this operator supports

compute_selector(input_schema: merlin.schema.schema.Schema, selector: merlin.dag.selector.ColumnSelector, parents_selector: Optional[merlin.dag.selector.ColumnSelector] = None, dependencies_selector: Optional[merlin.dag.selector.ColumnSelector] = None) → merlin.dag.selector.ColumnSelector[source]#

Provides a hook method for sub-classes to override to implement custom column selection logic.

Parameters

input_schema (Schema) – Schemas of the columns to apply this operator to
selector (ColumnSelector) – Column selector to apply to the input schema
parents_selector (ColumnSelector) – Combined selectors of the upstream parents feeding into this operator
dependencies_selector (ColumnSelector) – Combined selectors of the upstream dependencies feeding into this operator

Returns

Revised column selector to apply to the input schema

Return type

ColumnSelector

compute_input_schema(root_schema: merlin.schema.schema.Schema, parents_schema: merlin.schema.schema.Schema, deps_schema: merlin.schema.schema.Schema, selector: merlin.dag.selector.ColumnSelector) → merlin.schema.schema.Schema[source]#

Given the schemas coming from upstream sources and a column selector for the input columns, returns a set of schemas for the input columns this operator will use

Parameters

root_schema (Schema) – Base schema of the dataset before running any operators.
parents_schema (Schema) – The combined schemas of the upstream parents feeding into this operator
deps_schema (Schema) – The combined schemas of the upstream dependencies feeding into this operator
col_selector (ColumnSelector) – The column selector to apply to the input schema

Returns

The schemas of the columns used by this operator

Return type

Schema

compute_output_schema(input_schema: merlin.schema.schema.Schema, col_selector: merlin.dag.selector.ColumnSelector, prev_output_schema: Optional[merlin.schema.schema.Schema] = None) → merlin.schema.schema.Schema[source]#

Given a set of schemas and a column selector for the input columns, returns a set of schemas for the transformed columns this operator will produce

Parameters

input_schema (Schema) – The schemas of the columns to apply this operator to
col_selector (ColumnSelector) – The column selector to apply to the input schema

Returns

The schemas of the columns produced by this operator

Return type

Schema

validate_schemas(parents_schema: merlin.schema.schema.Schema, deps_schema: merlin.schema.schema.Schema, input_schema: merlin.schema.schema.Schema, output_schema: merlin.schema.schema.Schema, strict_dtypes: bool = False)[source]#

Provides a hook method that sub-classes can override to implement schema validation logic.

Sub-class implementations should raise an exception if the schemas are not valid for the operations they implement.

Parameters

parents_schema (Schema) – The combined schemas of the upstream parents feeding into this operator
deps_schema (Schema) – The combined schemas of the upstream dependencies feeding into this operator
input_schema (Schema) – The schemas of the columns to apply this operator to
output_schema (Schema) – The schemas of the columns produced by this operator
strict_dtypes (Boolean, optional) – Enables strict checking for column dtype matching if True, by default False

transform(col_selector: merlin.dag.selector.ColumnSelector, transformable: merlin.core.protocols.Transformable) → merlin.core.protocols.Transformable[source]#

Transform the dataframe by applying this operator to the set of input columns

Parameters

col_selector (ColumnSelector) – The columns to apply this operator to
transformable (Transformable) – A pandas or cudf dataframe that this operator will work on

Returns

Returns a transformed dataframe or dictarray for this operator

Return type

Transformable

column_mapping(col_selector)[source]#

Compute which output columns depend on which input columns

Parameters: col_selector (ColumnSelector) – A selector containing a list of column names
Returns: Mapping from output column names to list of the input columns they rely on
Return type: Dict[str, List[str]]

load_artifacts(artifact_path: Optional[os.PathLike] = None)[source]#

Load artifacts from disk required for operator function.

Parameters: artifact_path (str) – The path where artifacts are loaded from

save_artifacts(artifact_path: Optional[os.PathLike] = None) → None[source]#

Save artifacts required to be reload operator state from disk

Parameters: artifact_path (str) – The path where artifacts are to be saved

compute_column_schema(col_name, input_schema)[source]#

property dynamic_dtypes#

property is_subgraph#

output_column_names(col_selector: merlin.dag.selector.ColumnSelector) → merlin.dag.selector.ColumnSelector[source]#

Given a set of columns names returns the names of the transformed columns this operator will produce

Parameters: columns (list of str, or list of list of str) – The columns to apply this operator to
Returns: The names of columns produced by this operator
Return type: list of str, or list of list of str

property dependencies: List[Union[str, Any]]#

Defines an optional list of column dependencies for this operator. This lets you consume columns that aren’t part of the main transformation workflow.

Returns: Extra dependencies of this operator. Defaults to None
Return type: str, list of str or ColumnSelector, optional

property output_dtype#

property output_tags#

property output_properties#

property label: str#

create_node(selector)[source]#

property supports: merlin.dag.base_operator.Supports#: Returns what kind of data representation this operator supports

property supported_formats: merlin.dag.base_operator.DataFormats#