org.apache.spark.ml.feature

Class NGram

java.lang.Object

org.apache.spark.ml.PipelineStage

org.apache.spark.ml.Transformer

org.apache.spark.ml.UnaryTransformer<scala.collection.Seq<java.lang.String>,scala.collection.Seq<java.lang.String>,NGram>

org.apache.spark.ml.feature.NGram

All Implemented Interfaces:

java.io.Serializable, Logging, Params, Identifiable

public class NGram
extends UnaryTransformer<scala.collection.Seq<java.lang.String>,scala.collection.Seq<java.lang.String>,NGram>

:: Experimental :: A feature transformer that converts the input array of strings into an array of n-grams. Null values in the input array are ignored. It returns an array of n-grams where each n-gram is represented by a space-separated string of words.

When the input is empty, an empty array is returned. When the input array length is less than n (number of elements per n-gram), no n-grams are returned.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
NGram()
NGram(java.lang.String uid)

Method Summary

Methods

Modifier and Type	Method and Description
protected scala.Function1<scala.collection.Seq<java.lang.String>,scala.collection.Seq<java.lang.String>>	createTransformFunc() Creates the transform function using the given param map.
int	getN()
static NGram	load(java.lang.String path)
IntParam	n() Minimum n-gram length, >= 1.
protected DataType	outputDataType() Returns the data type of the output column.
NGram	setN(int value)
java.lang.String	uid() An immutable unique ID for the object and its derivatives.
protected void	validateInputType(DataType inputType) Validates the input type.

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

copy, setInputCol, setOutputCol, transform, transformSchema

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

transform, transform, transform

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

transformSchema

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.spark.Logging

initializeIfNecessary, initializeLogging, isTraceEnabled, log_, log, logDebug, logDebug, logError, logError, logInfo, logInfo, logName, logTrace, logTrace, logWarning, logWarning

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, validateParams

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

toString

Constructor Detail

NGram

public NGram(java.lang.String uid)

NGram

public NGram()

Method Detail

load

public static NGram load(java.lang.String path)

uid

public java.lang.String uid()

Description copied from interface: Identifiable

An immutable unique ID for the object and its derivatives.

Returns:

(undocumented)

n

public IntParam n()

Minimum n-gram length, >= 1. Default: 2, bigram features

Returns:

(undocumented)

setN

public NGram setN(int value)

getN

public int getN()

createTransformFunc

protected scala.Function1<scala.collection.Seq<java.lang.String>,scala.collection.Seq<java.lang.String>> createTransformFunc()

Description copied from class: UnaryTransformer

Creates the transform function using the given param map. The input param map already takes account of the embedded param map. So the param values should be determined solely by the input param map.

Specified by:

createTransformFunc in class UnaryTransformer<scala.collection.Seq<java.lang.String>,scala.collection.Seq<java.lang.String>,NGram>

Returns:

(undocumented)

validateInputType

protected void validateInputType(DataType inputType)

Description copied from class: UnaryTransformer

Validates the input type. Throw an exception if it is invalid.

Overrides:

validateInputType in class UnaryTransformer<scala.collection.Seq<java.lang.String>,scala.collection.Seq<java.lang.String>,NGram>

Parameters:

inputType - (undocumented)

outputDataType

protected DataType outputDataType()

Description copied from class: UnaryTransformer

Returns the data type of the output column.

Specified by:

outputDataType in class UnaryTransformer<scala.collection.Seq<java.lang.String>,scala.collection.Seq<java.lang.String>,NGram>

Returns:

(undocumented)