Imputer (Spark 2.4.1 JavaDoc)

Object
- org.apache.spark.ml.PipelineStage
- - org.apache.spark.ml.Estimator<ImputerModel>
  - - org.apache.spark.ml.feature.Imputer

All Implemented Interfaces:

java.io.Serializable, Logging, Params, DefaultParamsWritable, Identifiable, MLWritable
```
public class Imputer
extends Estimator<ImputerModel>
implements DefaultParamsWritable
```
:: Experimental :: Imputation estimator for completing missing values, either using the mean or the median of the columns in which the missing values are located. The input columns should be of DoubleType or FloatType. Currently Imputer does not support categorical features (SPARK-15041) and possibly creates incorrect values for a categorical feature.
Note that the mean/median value is computed after filtering out missing values. All Null values in the input columns are treated as missing, and so are also imputed. For computing median, DataFrameStatFunctions.approxQuantile is used with a relative error of 0.001.

See Also:

Serialized Form

Constructor Summary

Constructors
Constructor and Description

Imputer()

Imputer(String uid)

Constructors
Constructor and Description
`Imputer()`
`Imputer(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)`
`Imputer`	`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)`
`ImputerModel`	`fit(Dataset<?> dataset)` Fits a model to the input data.
`static <T> scala.Option<T>`	`get(Param<T> param)`
`static <T> scala.Option<T>`	`getDefault(Param<T> param)`
`static String[]`	`getInputCols()`
`static double`	`getMissingValue()`
`double`	`getMissingValue()`
`static <T> T`	`getOrDefault(Param<T> param)`
`static String[]`	`getOutputCols()`
`static Param<Object>`	`getParam(String paramName)`
`static String`	`getStrategy()`
`String`	`getStrategy()`
`static <T> boolean`	`hasDefault(Param<T> param)`
`static boolean`	`hasParam(String paramName)`
`static StringArrayParam`	`inputCols()`
`static boolean`	`isDefined(Param<?> param)`
`static boolean`	`isSet(Param<?> param)`
`static Imputer`	`load(String path)`
`static DoubleParam`	`missingValue()`
`DoubleParam`	`missingValue()` The placeholder for the missing values.
`static StringArrayParam`	`outputCols()`
`static Param<?>[]`	`params()`
`static void`	`save(String path)`
`static <T> Params`	`set(Param<T> param, T value)`
`Imputer`	`setInputCols(String[] value)`
`Imputer`	`setMissingValue(double value)`
`Imputer`	`setOutputCols(String[] value)`
`Imputer`	`setStrategy(String value)` Imputation strategy.
`static Param<String>`	`strategy()`
`Param<String>`	`strategy()` The imputation strategy.
`static String`	`toString()`
`StructType`	`transformSchema(StructType schema)` :: DeveloperApi ::
`String`	`uid()` An immutable unique ID for the object and its derivatives.
`StructType`	`validateAndTransformSchema(StructType schema)` Validates and transforms the input schema.
`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.HasInputCols
getInputCols, inputCols

Methods inherited from interface org.apache.spark.ml.param.shared.HasOutputCols
getOutputCols, outputCols

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
  - Imputer
```
public Imputer(String uid)
```
  - Imputer
```
public Imputer()
```
- Method Detail
  - load
```
public static Imputer 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()
```
  - inputCols
```
public static final StringArrayParam inputCols()
```
  - getInputCols
```
public static final String[] getInputCols()
```
  - outputCols
```
public static final StringArrayParam outputCols()
```
  - getOutputCols
```
public static final String[] getOutputCols()
```
  - strategy
```
public static final Param<String> strategy()
```
  - getStrategy
```
public static String getStrategy()
```
  - missingValue
```
public static final DoubleParam missingValue()
```
  - getMissingValue
```
public static double getMissingValue()
```
  - 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)
  - setInputCols
```
public Imputer setInputCols(String[] value)
```
  - setOutputCols
```
public Imputer setOutputCols(String[] value)
```
  - setStrategy
```
public Imputer setStrategy(String value)
```
    Imputation strategy. Available options are ["mean", "median"].
    
    Parameters:
    
    value - (undocumented)
    
    Returns:
    
    (undocumented)
  - setMissingValue
```
public Imputer setMissingValue(double value)
```
  - fit
```
public ImputerModel fit(Dataset<?> dataset)
```
    Description copied from class: Estimator
    
    Fits a model to the input data.
    
    Specified by:
    
    fit in class Estimator<ImputerModel>
    
    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 Imputer 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<ImputerModel>
    
    Parameters:
    
    extra - (undocumented)
    
    Returns:
    
    (undocumented)
  - getMissingValue
```
public double getMissingValue()
```
  - getStrategy
```
public String getStrategy()
```
  - missingValue
```
public DoubleParam missingValue()
```
    The placeholder for the missing values. All occurrences of missingValue will be imputed. Note that null values are always treated as missing. Default: Double.NaN
    
    Returns:
    
    (undocumented)
  - strategy
```
public Param<String> strategy()
```
    The imputation strategy. Currently only "mean" and "median" are supported. If "mean", then replace missing values using the mean value of the feature. If "median", then replace missing values using the approximate median value of the feature. Default: mean
    
    Returns:
    
    (undocumented)
  - validateAndTransformSchema
```
public StructType validateAndTransformSchema(StructType schema)
```
    Validates and transforms the input schema.

Class Imputer

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.HasInputCols

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

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

Imputer

Imputer

Method Detail

load

toString

params

explainParam

explainParams

isSet

isDefined

hasParam

getParam

set

get

clear

getOrDefault

getDefault

hasDefault

extractParamMap

extractParamMap

inputCols

getInputCols

outputCols

getOutputCols

strategy

getStrategy

missingValue

getMissingValue

save

write

uid

setInputCols

setOutputCols

setStrategy

setMissingValue

fit

transformSchema

copy

getMissingValue

getStrategy

missingValue

strategy

validateAndTransformSchema