Packages

class VectorIndexer extends Estimator[VectorIndexerModel] with VectorIndexerParams with DefaultParamsWritable

Class for indexing categorical feature columns in a dataset of Vector.

This has 2 usage modes:

  • Automatically identify categorical features (default behavior)
    • This helps process a dataset of unknown vectors into a dataset with some continuous features and some categorical features. The choice between continuous and categorical is based upon a maxCategories parameter.
    • Set maxCategories to the maximum number of categorical any categorical feature should have.
    • E.g.: Feature 0 has unique values {-1.0, 0.0}, and feature 1 values {1.0, 3.0, 5.0}. If maxCategories = 2, then feature 0 will be declared categorical and use indices {0, 1}, and feature 1 will be declared continuous.
  • Index all features, if all features are categorical
    • If maxCategories is set to be very large, then this will build an index of unique values for all features.
    • Warning: This can cause problems if features are continuous since this will collect ALL unique values to the driver.
    • E.g.: Feature 0 has unique values {-1.0, 0.0}, and feature 1 values {1.0, 3.0, 5.0}. If maxCategories is greater than or equal to 3, then both features will be declared categorical.

This returns a model which can transform categorical features to use 0-based indices.

Index stability:

  • This is not guaranteed to choose the same category index across multiple runs.
  • If a categorical feature includes value 0, then this is guaranteed to map value 0 to index 0. This maintains vector sparsity.
  • More stability may be added in the future.

TODO: Future extensions: The following functionality is planned for the future:

  • Preserve metadata in transform; if a feature's metadata is already present, do not recompute.
  • Specify certain features to not index, either via a parameter or via existing metadata.
  • Add warning if a categorical feature has only 1 category.
Annotations
@Since( "1.4.0" )
Source
VectorIndexer.scala
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Inherited
  1. VectorIndexer
  2. DefaultParamsWritable
  3. MLWritable
  4. VectorIndexerParams
  5. HasHandleInvalid
  6. HasOutputCol
  7. HasInputCol
  8. Estimator
  9. PipelineStage
  10. Logging
  11. Params
  12. Serializable
  13. Serializable
  14. Identifiable
  15. AnyRef
  16. Any
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Visibility
  1. Public
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Parameters

A list of (hyper-)parameter keys this algorithm can take. Users can set and get the parameter values through setters and getters, respectively.

  1. val handleInvalid: Param[String]

    Param for how to handle invalid data (unseen labels or NULL values).

    Param for how to handle invalid data (unseen labels or NULL values). Note: this param only applies to categorical features, not continuous ones. Options are: 'skip': filter out rows with invalid data. 'error': throw an error. 'keep': put invalid data in a special additional bucket, at index of the number of categories of the feature. Default value: "error"

    Definition Classes
    VectorIndexerParams → HasHandleInvalid
    Annotations
    @Since( "2.3.0" )
  2. final val inputCol: Param[String]

    Param for input column name.

    Param for input column name.

    Definition Classes
    HasInputCol
  3. val maxCategories: IntParam

    Threshold for the number of values a categorical feature can take.

    Threshold for the number of values a categorical feature can take. If a feature is found to have > maxCategories values, then it is declared continuous. Must be greater than or equal to 2.

    (default = 20)

    Definition Classes
    VectorIndexerParams
  4. final val outputCol: Param[String]

    Param for output column name.

    Param for output column name.

    Definition Classes
    HasOutputCol

Members

  1. final def clear(param: Param[_]): VectorIndexer.this.type

    Clears the user-supplied value for the input param.

    Clears the user-supplied value for the input param.

    Definition Classes
    Params
  2. def copy(extra: ParamMap): VectorIndexer

    Creates a copy of this instance with the same UID and some extra params.

    Creates a copy of this instance with the same UID and some extra params. Subclasses should implement this method and set the return type properly. See defaultCopy().

    Definition Classes
    VectorIndexerEstimatorPipelineStageParams
    Annotations
    @Since( "1.4.1" )
  3. def explainParam(param: Param[_]): String

    Explains a param.

    Explains a param.

    param

    input param, must belong to this instance.

    returns

    a string that contains the input param name, doc, and optionally its default value and the user-supplied value

    Definition Classes
    Params
  4. def explainParams(): String

    Explains all params of this instance.

    Explains all params of this instance. See explainParam().

    Definition Classes
    Params
  5. final def extractParamMap(): ParamMap

    extractParamMap with no extra values.

    extractParamMap with no extra values.

    Definition Classes
    Params
  6. final def extractParamMap(extra: ParamMap): ParamMap

    Extracts the embedded default param values and user-supplied values, and then merges them with extra values from input into a flat param map, where the latter value is used if there exist conflicts, i.e., with ordering: default param values less than user-supplied values less than extra.

    Extracts the embedded default param values and user-supplied values, and then merges them with extra values from input into a flat param map, where the latter value is used if there exist conflicts, i.e., with ordering: default param values less than user-supplied values less than extra.

    Definition Classes
    Params
  7. def fit(dataset: Dataset[_]): VectorIndexerModel

    Fits a model to the input data.

    Fits a model to the input data.

    Definition Classes
    VectorIndexerEstimator
    Annotations
    @Since( "2.0.0" )
  8. def fit(dataset: Dataset[_], paramMaps: Seq[ParamMap]): Seq[VectorIndexerModel]

    Fits multiple models to the input data with multiple sets of parameters.

    Fits multiple models to the input data with multiple sets of parameters. The default implementation uses a for loop on each parameter map. Subclasses could override this to optimize multi-model training.

    dataset

    input dataset

    paramMaps

    An array of parameter maps. These values override any specified in this Estimator's embedded ParamMap.

    returns

    fitted models, matching the input parameter maps

    Definition Classes
    Estimator
    Annotations
    @Since( "2.0.0" )
  9. def fit(dataset: Dataset[_], paramMap: ParamMap): VectorIndexerModel

    Fits a single model to the input data with provided parameter map.

    Fits a single model to the input data with provided parameter map.

    dataset

    input dataset

    paramMap

    Parameter map. These values override any specified in this Estimator's embedded ParamMap.

    returns

    fitted model

    Definition Classes
    Estimator
    Annotations
    @Since( "2.0.0" )
  10. def fit(dataset: Dataset[_], firstParamPair: ParamPair[_], otherParamPairs: ParamPair[_]*): VectorIndexerModel

    Fits a single model to the input data with optional parameters.

    Fits a single model to the input data with optional parameters.

    dataset

    input dataset

    firstParamPair

    the first param pair, overrides embedded params

    otherParamPairs

    other param pairs. These values override any specified in this Estimator's embedded ParamMap.

    returns

    fitted model

    Definition Classes
    Estimator
    Annotations
    @Since( "2.0.0" ) @varargs()
  11. final def get[T](param: Param[T]): Option[T]

    Optionally returns the user-supplied value of a param.

    Optionally returns the user-supplied value of a param.

    Definition Classes
    Params
  12. final def getDefault[T](param: Param[T]): Option[T]

    Gets the default value of a parameter.

    Gets the default value of a parameter.

    Definition Classes
    Params
  13. final def getOrDefault[T](param: Param[T]): T

    Gets the value of a param in the embedded param map or its default value.

    Gets the value of a param in the embedded param map or its default value. Throws an exception if neither is set.

    Definition Classes
    Params
  14. def getParam(paramName: String): Param[Any]

    Gets a param by its name.

    Gets a param by its name.

    Definition Classes
    Params
  15. final def hasDefault[T](param: Param[T]): Boolean

    Tests whether the input param has a default value set.

    Tests whether the input param has a default value set.

    Definition Classes
    Params
  16. def hasParam(paramName: String): Boolean

    Tests whether this instance contains a param with a given name.

    Tests whether this instance contains a param with a given name.

    Definition Classes
    Params
  17. final def isDefined(param: Param[_]): Boolean

    Checks whether a param is explicitly set or has a default value.

    Checks whether a param is explicitly set or has a default value.

    Definition Classes
    Params
  18. final def isSet(param: Param[_]): Boolean

    Checks whether a param is explicitly set.

    Checks whether a param is explicitly set.

    Definition Classes
    Params
  19. lazy val params: Array[Param[_]]

    Returns all params sorted by their names.

    Returns all params sorted by their names. The default implementation uses Java reflection to list all public methods that have no arguments and return Param.

    Definition Classes
    Params
    Note

    Developer should not use this method in constructor because we cannot guarantee that this variable gets initialized before other params.

  20. def save(path: String): Unit

    Saves this ML instance to the input path, a shortcut of write.save(path).

    Saves this ML instance to the input path, a shortcut of write.save(path).

    Definition Classes
    MLWritable
    Annotations
    @Since( "1.6.0" ) @throws( ... )
  21. final def set[T](param: Param[T], value: T): VectorIndexer.this.type

    Sets a parameter in the embedded param map.

    Sets a parameter in the embedded param map.

    Definition Classes
    Params
  22. def toString(): String
    Definition Classes
    Identifiable → AnyRef → Any
  23. def transformSchema(schema: StructType): StructType

    Check transform validity and derive the output schema from the input schema.

    Check transform validity and derive the output schema from the input schema.

    We check validity for interactions between parameters during transformSchema and raise an exception if any parameter value is invalid. Parameter value checks which do not depend on other parameters are handled by Param.validate().

    Typical implementation should first conduct verification on schema change and parameter validity, including complex parameter interaction checks.

    Definition Classes
    VectorIndexerPipelineStage
    Annotations
    @Since( "1.4.0" )
  24. val uid: String

    An immutable unique ID for the object and its derivatives.

    An immutable unique ID for the object and its derivatives.

    Definition Classes
    VectorIndexerIdentifiable
    Annotations
    @Since( "1.4.0" )
  25. def write: MLWriter

    Returns an MLWriter instance for this ML instance.

    Returns an MLWriter instance for this ML instance.

    Definition Classes
    DefaultParamsWritableMLWritable

Parameter setters

  1. def setHandleInvalid(value: String): VectorIndexer.this.type

    Annotations
    @Since( "2.3.0" )
  2. def setInputCol(value: String): VectorIndexer.this.type

    Annotations
    @Since( "1.4.0" )
  3. def setMaxCategories(value: Int): VectorIndexer.this.type

    Annotations
    @Since( "1.4.0" )
  4. def setOutputCol(value: String): VectorIndexer.this.type

    Annotations
    @Since( "1.4.0" )

Parameter getters

  1. final def getHandleInvalid: String

    Definition Classes
    HasHandleInvalid
  2. final def getInputCol: String

    Definition Classes
    HasInputCol
  3. def getMaxCategories: Int

    Definition Classes
    VectorIndexerParams
  4. final def getOutputCol: String

    Definition Classes
    HasOutputCol