final class UnivariateFeatureSelector extends Estimator[UnivariateFeatureSelectorModel] with UnivariateFeatureSelectorParams with DefaultParamsWritable
Feature selector based on univariate statistical tests against labels. Currently, Spark
supports three Univariate Feature Selectors: chi-squared, ANOVA F-test and F-value.
User can choose Univariate Feature Selector by setting featureType
and labelType
,
and Spark will pick the score function based on the specified featureType
and labelType
.
The following combination of featureType
and labelType
are supported:
featureType
categorical
andlabelType
categorical
: Spark uses chi-squared, i.e. chi2 in sklearn.featureType
continuous
andlabelType
categorical
: Spark uses ANOVA F-test, i.e. f_classif in sklearn.featureType
continuous
andlabelType
continuous
: Spark uses F-value, i.e. f_regression in sklearn.
The UnivariateFeatureSelector
supports different selection modes: numTopFeatures
,
percentile
, fpr
, fdr
, fwe
.
numTopFeatures
chooses a fixed number of top features according to a hypothesis.percentile
is similar but chooses a fraction of all features instead of a fixed number.fpr
chooses all features whose p-value are below a threshold, thus controlling the false positive rate of selection.fdr
uses the Benjamini-Hochberg procedure to choose all features whose false discovery rate is below a threshold.fwe
chooses all features whose p-values are below a threshold. The threshold is scaled by 1/numFeatures, thus controlling the family-wise error rate of selection.
By default, the selection mode is numTopFeatures
.
- Annotations
- @Since( "3.1.1" )
- Source
- UnivariateFeatureSelector.scala
- Grouped
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- UnivariateFeatureSelector
- DefaultParamsWritable
- MLWritable
- UnivariateFeatureSelectorParams
- HasOutputCol
- HasLabelCol
- HasFeaturesCol
- Estimator
- PipelineStage
- Logging
- Params
- Serializable
- Serializable
- Identifiable
- AnyRef
- Any
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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.
-
final
val
featureType: Param[String]
The feature type.
The feature type. Supported options: "categorical", "continuous"
- Definition Classes
- UnivariateFeatureSelectorParams
- Annotations
- @Since( "3.1.1" )
-
final
val
featuresCol: Param[String]
Param for features column name.
Param for features column name.
- Definition Classes
- HasFeaturesCol
-
final
val
labelCol: Param[String]
Param for label column name.
Param for label column name.
- Definition Classes
- HasLabelCol
-
final
val
labelType: Param[String]
The label type.
The label type. Supported options: "categorical", "continuous"
- Definition Classes
- UnivariateFeatureSelectorParams
- Annotations
- @Since( "3.1.1" )
-
final
val
outputCol: Param[String]
Param for output column name.
Param for output column name.
- Definition Classes
- HasOutputCol
-
final
val
selectionMode: Param[String]
The selection mode.
The selection mode. Supported options: "numTopFeatures" (default), "percentile", "fpr", "fdr", "fwe"
- Definition Classes
- UnivariateFeatureSelectorParams
- Annotations
- @Since( "3.1.1" )
-
final
val
selectionThreshold: DoubleParam
The upper bound of the features that selector will select.
The upper bound of the features that selector will select.
- Definition Classes
- UnivariateFeatureSelectorParams
- Annotations
- @Since( "3.1.1" )
Members
-
final
def
clear(param: Param[_]): UnivariateFeatureSelector.this.type
Clears the user-supplied value for the input param.
Clears the user-supplied value for the input param.
- Definition Classes
- Params
-
def
copy(extra: ParamMap): UnivariateFeatureSelector
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
- UnivariateFeatureSelector → Estimator → PipelineStage → Params
- Annotations
- @Since( "3.1.1" )
-
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
-
def
explainParams(): String
Explains all params of this instance.
Explains all params of this instance. See
explainParam()
.- Definition Classes
- Params
-
final
def
extractParamMap(): ParamMap
extractParamMap
with no extra values.extractParamMap
with no extra values.- Definition Classes
- Params
-
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
-
def
fit(dataset: Dataset[_]): UnivariateFeatureSelectorModel
Fits a model to the input data.
Fits a model to the input data.
- Definition Classes
- UnivariateFeatureSelector → Estimator
- Annotations
- @Since( "3.1.1" )
-
def
fit(dataset: Dataset[_], paramMaps: Seq[ParamMap]): Seq[UnivariateFeatureSelectorModel]
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" )
-
def
fit(dataset: Dataset[_], paramMap: ParamMap): UnivariateFeatureSelectorModel
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" )
-
def
fit(dataset: Dataset[_], firstParamPair: ParamPair[_], otherParamPairs: ParamPair[_]*): UnivariateFeatureSelectorModel
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()
-
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
-
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
-
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
-
def
getParam(paramName: String): Param[Any]
Gets a param by its name.
Gets a param by its name.
- Definition Classes
- Params
-
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
-
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
-
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
-
final
def
isSet(param: Param[_]): Boolean
Checks whether a param is explicitly set.
Checks whether a param is explicitly set.
- Definition Classes
- Params
-
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.
-
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( ... )
-
final
def
set[T](param: Param[T], value: T): UnivariateFeatureSelector.this.type
Sets a parameter in the embedded param map.
Sets a parameter in the embedded param map.
- Definition Classes
- Params
-
def
toString(): String
- Definition Classes
- Identifiable → AnyRef → Any
-
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 byParam.validate()
.Typical implementation should first conduct verification on schema change and parameter validity, including complex parameter interaction checks.
- Definition Classes
- UnivariateFeatureSelector → PipelineStage
- Annotations
- @Since( "3.1.1" )
-
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
- UnivariateFeatureSelector → Identifiable
- Annotations
- @Since( "3.1.1" )
-
def
write: MLWriter
Returns an
MLWriter
instance for this ML instance.Returns an
MLWriter
instance for this ML instance.- Definition Classes
- DefaultParamsWritable → MLWritable
Parameter setters
-
def
setFeatureType(value: String): UnivariateFeatureSelector.this.type
- Annotations
- @Since( "3.1.1" )
-
def
setFeaturesCol(value: String): UnivariateFeatureSelector.this.type
- Annotations
- @Since( "3.1.1" )
-
def
setLabelCol(value: String): UnivariateFeatureSelector.this.type
- Annotations
- @Since( "3.1.1" )
-
def
setLabelType(value: String): UnivariateFeatureSelector.this.type
- Annotations
- @Since( "3.1.1" )
-
def
setOutputCol(value: String): UnivariateFeatureSelector.this.type
- Annotations
- @Since( "3.1.1" )
-
def
setSelectionMode(value: String): UnivariateFeatureSelector.this.type
- Annotations
- @Since( "3.1.1" )
-
def
setSelectionThreshold(value: Double): UnivariateFeatureSelector.this.type
- Annotations
- @Since( "3.1.1" )
Parameter getters
-
def
getFeatureType: String
- Definition Classes
- UnivariateFeatureSelectorParams
- Annotations
- @Since( "3.1.1" )
-
final
def
getFeaturesCol: String
- Definition Classes
- HasFeaturesCol
-
final
def
getLabelCol: String
- Definition Classes
- HasLabelCol
-
def
getLabelType: String
- Definition Classes
- UnivariateFeatureSelectorParams
- Annotations
- @Since( "3.1.1" )
-
final
def
getOutputCol: String
- Definition Classes
- HasOutputCol
-
def
getSelectionMode: String
- Definition Classes
- UnivariateFeatureSelectorParams
- Annotations
- @Since( "3.1.1" )
-
def
getSelectionThreshold: Double
- Definition Classes
- UnivariateFeatureSelectorParams