ChiSqSelector (Spark 2.3.2 JavaDoc)

Object
- org.apache.spark.ml.PipelineStage
- - org.apache.spark.ml.Estimator<ChiSqSelectorModel>
  - - org.apache.spark.ml.feature.ChiSqSelector

All Implemented Interfaces:

java.io.Serializable, Logging, Params, DefaultParamsWritable, Identifiable, MLWritable
```
public final class ChiSqSelector
extends Estimator<ChiSqSelectorModel>
implements DefaultParamsWritable
```
Chi-Squared feature selection, which selects categorical features to use for predicting a categorical label. The selector supports different selection methods: numTopFeatures, percentile, fpr, fdr, fwe. - numTopFeatures chooses a fixed number of top features according to a chi-squared test. - 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] (https://en.wikipedia.org/wiki/False_discovery_rate#Benjamini.E2.80.93Hochberg_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 method is numTopFeatures, with the default number of top features set to 50.

See Also:

Serialized Form

Constructor Summary

Constructors
Constructor and Description

ChiSqSelector()

ChiSqSelector(String uid)

Constructors
Constructor and Description
`ChiSqSelector()`
`ChiSqSelector(String uid)`

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`static Params`	`clear(Param<?> param)`
`ChiSqSelector`	`copy(ParamMap extra)` Creates a copy of this instance with the same UID and some extra params.
`static String`	`explainParam(Param<?> param)`
`static String`	`explainParams()`
`static ParamMap`	`extractParamMap()`
`static ParamMap`	`extractParamMap(ParamMap extra)`
`static DoubleParam`	`fdr()`
`DoubleParam`	`fdr()` The upper bound of the expected false discovery rate.
`static Param<String>`	`featuresCol()`
`ChiSqSelectorModel`	`fit(Dataset<?> dataset)` Fits a model to the input data.
`static DoubleParam`	`fpr()`
`DoubleParam`	`fpr()` The highest p-value for features to be kept.
`static DoubleParam`	`fwe()`
`DoubleParam`	`fwe()` The upper bound of the expected family-wise error rate.
`static <T> scala.Option<T>`	`get(Param<T> param)`
`static <T> scala.Option<T>`	`getDefault(Param<T> param)`
`static double`	`getFdr()`
`double`	`getFdr()`
`static String`	`getFeaturesCol()`
`static double`	`getFpr()`
`double`	`getFpr()`
`static double`	`getFwe()`
`double`	`getFwe()`
`static String`	`getLabelCol()`
`static int`	`getNumTopFeatures()`
`int`	`getNumTopFeatures()`
`static <T> T`	`getOrDefault(Param<T> param)`
`static String`	`getOutputCol()`
`static Param<Object>`	`getParam(String paramName)`
`static double`	`getPercentile()`
`double`	`getPercentile()`
`static String`	`getSelectorType()`
`String`	`getSelectorType()`
`static <T> boolean`	`hasDefault(Param<T> param)`
`static boolean`	`hasParam(String paramName)`
`static boolean`	`isDefined(Param<?> param)`
`static boolean`	`isSet(Param<?> param)`
`static Param<String>`	`labelCol()`
`static ChiSqSelector`	`load(String path)`
`static IntParam`	`numTopFeatures()`
`IntParam`	`numTopFeatures()` Number of features that selector will select, ordered by ascending p-value.
`static Param<String>`	`outputCol()`
`static Param<?>[]`	`params()`
`static DoubleParam`	`percentile()`
`DoubleParam`	`percentile()` Percentile of features that selector will select, ordered by statistics value descending.
`static void`	`save(String path)`
`static Param<String>`	`selectorType()`
`Param<String>`	`selectorType()` The selector type of the ChisqSelector.
`static <T> Params`	`set(Param<T> param, T value)`
`ChiSqSelector`	`setFdr(double value)`
`ChiSqSelector`	`setFeaturesCol(String value)`
`ChiSqSelector`	`setFpr(double value)`
`ChiSqSelector`	`setFwe(double value)`
`ChiSqSelector`	`setLabelCol(String value)`
`ChiSqSelector`	`setNumTopFeatures(int value)`
`ChiSqSelector`	`setOutputCol(String value)`
`ChiSqSelector`	`setPercentile(double value)`
`ChiSqSelector`	`setSelectorType(String value)`
`static String`	`toString()`
`StructType`	`transformSchema(StructType schema)` :: DeveloperApi ::
`String`	`uid()` An immutable unique ID for the object and its derivatives.
`static MLWriter`	`write()`

Methods inherited from class org.apache.spark.ml.Estimator
fit, fit, fit, fit

Methods inherited from class Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.spark.ml.param.shared.HasFeaturesCol
featuresCol, getFeaturesCol

Methods inherited from interface org.apache.spark.ml.param.shared.HasOutputCol
getOutputCol, outputCol

Methods inherited from interface org.apache.spark.ml.param.shared.HasLabelCol
getLabelCol, labelCol

Methods inherited from interface org.apache.spark.ml.param.Params
clear, copyValues, defaultCopy, defaultParamMap, explainParam, explainParams, extractParamMap, extractParamMap, get, getDefault, getOrDefault, getParam, hasDefault, hasParam, isDefined, isSet, paramMap, params, set, set, set, setDefault, setDefault, shouldOwn

Methods inherited from interface org.apache.spark.ml.util.Identifiable
toString

Methods inherited from interface org.apache.spark.ml.util.DefaultParamsWritable
write

Methods inherited from interface org.apache.spark.ml.util.MLWritable
save

Methods inherited from interface org.apache.spark.internal.Logging
initializeLogging, initializeLogIfNecessary, initializeLogIfNecessary, isTraceEnabled, log_, log, logDebug, logDebug, logError, logError, logInfo, logInfo, logName, logTrace, logTrace, logWarning, logWarning

- Constructor Detail
  - ChiSqSelector
```
public ChiSqSelector(String uid)
```
  - ChiSqSelector
```
public ChiSqSelector()
```
- Method Detail
  - load
```
public static ChiSqSelector load(String path)
```
  - toString
```
public static String toString()
```
  - params
```
public static Param<?>[] params()
```
  - explainParam
```
public static String explainParam(Param<?> param)
```
  - explainParams
```
public static String explainParams()
```
  - isSet
```
public static final boolean isSet(Param<?> param)
```
  - isDefined
```
public static final boolean isDefined(Param<?> param)
```
  - hasParam
```
public static boolean hasParam(String paramName)
```
  - getParam
```
public static Param<Object> getParam(String paramName)
```
  - set
```
public static final <T> Params set(Param<T> param,
                                   T value)
```
  - get
```
public static final <T> scala.Option<T> get(Param<T> param)
```
  - clear
```
public static final Params clear(Param<?> param)
```
  - getOrDefault
```
public static final <T> T getOrDefault(Param<T> param)
```
  - getDefault
```
public static final <T> scala.Option<T> getDefault(Param<T> param)
```
  - hasDefault
```
public static final <T> boolean hasDefault(Param<T> param)
```
  - extractParamMap
```
public static final ParamMap extractParamMap(ParamMap extra)
```
  - extractParamMap
```
public static final ParamMap extractParamMap()
```
  - featuresCol
```
public static final Param<String> featuresCol()
```
  - getFeaturesCol
```
public static final String getFeaturesCol()
```
  - outputCol
```
public static final Param<String> outputCol()
```
  - getOutputCol
```
public static final String getOutputCol()
```
  - labelCol
```
public static final Param<String> labelCol()
```
  - getLabelCol
```
public static final String getLabelCol()
```
  - numTopFeatures
```
public static final IntParam numTopFeatures()
```
  - getNumTopFeatures
```
public static int getNumTopFeatures()
```
  - percentile
```
public static final DoubleParam percentile()
```
  - getPercentile
```
public static double getPercentile()
```
  - fpr
```
public static final DoubleParam fpr()
```
  - getFpr
```
public static double getFpr()
```
  - fdr
```
public static final DoubleParam fdr()
```
  - getFdr
```
public static double getFdr()
```
  - fwe
```
public static final DoubleParam fwe()
```
  - getFwe
```
public static double getFwe()
```
  - selectorType
```
public static final Param<String> selectorType()
```
  - getSelectorType
```
public static String getSelectorType()
```
  - save
```
public static void save(String path)
                 throws java.io.IOException
```
    Throws:
    
    java.io.IOException
  - write
```
public static MLWriter write()
```
  - uid
```
public String uid()
```
    Description copied from interface: Identifiable
    
    An immutable unique ID for the object and its derivatives.
    
    Specified by:
    
    uid in interface Identifiable
    
    Returns:
    
    (undocumented)
  - setNumTopFeatures
```
public ChiSqSelector setNumTopFeatures(int value)
```
  - setPercentile
```
public ChiSqSelector setPercentile(double value)
```
  - setFpr
```
public ChiSqSelector setFpr(double value)
```
  - setFdr
```
public ChiSqSelector setFdr(double value)
```
  - setFwe
```
public ChiSqSelector setFwe(double value)
```
  - setSelectorType
```
public ChiSqSelector setSelectorType(String value)
```
  - setFeaturesCol
```
public ChiSqSelector setFeaturesCol(String value)
```
  - setOutputCol
```
public ChiSqSelector setOutputCol(String value)
```
  - setLabelCol
```
public ChiSqSelector setLabelCol(String value)
```
  - fit
```
public ChiSqSelectorModel fit(Dataset<?> dataset)
```
    Description copied from class: Estimator
    
    Fits a model to the input data.
    
    Specified by:
    
    fit in class Estimator<ChiSqSelectorModel>
    
    Parameters:
    
    dataset - (undocumented)
    
    Returns:
    
    (undocumented)
  - transformSchema
```
public StructType transformSchema(StructType schema)
```
    Description copied from class: PipelineStage
    
    :: DeveloperApi ::
    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.
    
    Specified by:
    
    transformSchema in class PipelineStage
    
    Parameters:
    
    schema - (undocumented)
    
    Returns:
    
    (undocumented)
  - copy
```
public ChiSqSelector copy(ParamMap extra)
```
    Description copied from interface: 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().
    
    Specified by:
    
    copy in interface Params
    
    Specified by:
    
    copy in class Estimator<ChiSqSelectorModel>
    
    Parameters:
    
    extra - (undocumented)
    
    Returns:
    
    (undocumented)
  - numTopFeatures
```
public IntParam numTopFeatures()
```
    Number of features that selector will select, ordered by ascending p-value. If the number of features is less than numTopFeatures, then this will select all features. Only applicable when selectorType = "numTopFeatures". The default value of numTopFeatures is 50.
    
    Returns:
    
    (undocumented)
  - getNumTopFeatures
```
public int getNumTopFeatures()
```
  - percentile
```
public DoubleParam percentile()
```
    Percentile of features that selector will select, ordered by statistics value descending. Only applicable when selectorType = "percentile". Default value is 0.1.
    
    Returns:
    
    (undocumented)
  - getPercentile
```
public double getPercentile()
```
  - fpr
```
public DoubleParam fpr()
```
    The highest p-value for features to be kept. Only applicable when selectorType = "fpr". Default value is 0.05.
    
    Returns:
    
    (undocumented)
  - getFpr
```
public double getFpr()
```
  - fdr
```
public DoubleParam fdr()
```
    The upper bound of the expected false discovery rate. Only applicable when selectorType = "fdr". Default value is 0.05.
    
    Returns:
    
    (undocumented)
  - getFdr
```
public double getFdr()
```
  - fwe
```
public DoubleParam fwe()
```
    The upper bound of the expected family-wise error rate. Only applicable when selectorType = "fwe". Default value is 0.05.
    
    Returns:
    
    (undocumented)
  - getFwe
```
public double getFwe()
```
  - selectorType
```
public Param<String> selectorType()
```
    The selector type of the ChisqSelector. Supported options: "numTopFeatures" (default), "percentile", "fpr", "fdr", "fwe".
    
    Returns:
    
    (undocumented)
  - getSelectorType
```
public String getSelectorType()
```

Class ChiSqSelector

Constructor Summary

Method Summary

Methods inherited from class org.apache.spark.ml.Estimator

Methods inherited from class Object

Methods inherited from interface org.apache.spark.ml.param.shared.HasFeaturesCol

Methods inherited from interface org.apache.spark.ml.param.shared.HasOutputCol

Methods inherited from interface org.apache.spark.ml.param.shared.HasLabelCol

Methods inherited from interface org.apache.spark.ml.param.Params

Methods inherited from interface org.apache.spark.ml.util.Identifiable

Methods inherited from interface org.apache.spark.ml.util.DefaultParamsWritable

Methods inherited from interface org.apache.spark.ml.util.MLWritable

Methods inherited from interface org.apache.spark.internal.Logging

Constructor Detail

ChiSqSelector

ChiSqSelector

Method Detail

load

toString

params

explainParam

explainParams

isSet

isDefined

hasParam

getParam

set

get

clear

getOrDefault

getDefault

hasDefault

extractParamMap

extractParamMap

featuresCol

getFeaturesCol

outputCol

getOutputCol

labelCol

getLabelCol

numTopFeatures

getNumTopFeatures

percentile

getPercentile

fpr

getFpr

fdr

getFdr

fwe

getFwe

selectorType

getSelectorType

save

write

uid

setNumTopFeatures

setPercentile

setFpr

setFdr

setFwe

setSelectorType

setFeaturesCol

setOutputCol

setLabelCol

fit

transformSchema

copy

numTopFeatures

getNumTopFeatures

percentile

getPercentile

fpr

getFpr

fdr

getFdr

fwe

getFwe

selectorType

getSelectorType