org.apache.ignite.ml.preprocessing.encoding.stringencoder

Class StringEncoderPreprocessor<K,V>

java.lang.Object

org.apache.ignite.ml.preprocessing.encoding.EncoderPreprocessor<K,V>

org.apache.ignite.ml.preprocessing.encoding.stringencoder.StringEncoderPreprocessor<K,V>

Type Parameters:

K - Type of a key in upstream data.

V - Type of a value in upstream data.

All Implemented Interfaces:

Serializable, BiFunction<K,V,Vector>, IgniteBiFunction<K,V,Vector>

public class StringEncoderPreprocessor<K,V>
extends EncoderPreprocessor<K,V>

Preprocessing function that makes String encoding. The String Encoder Preprocessor encodes string values (categories) to double values in range [0.0, amountOfCategories), where the most popular value will be presented as 0.0 and the least popular value presented with amountOfCategories-1 value.

This preprocessor can transform multiple columns which indices are handled during training process. These indexes could be defined via .withEncodedFeature(featureIndex) call.

NOTE: it doesn?t add new column but change data in-place.

There is only a one strategy regarding how StringEncoder will handle unseen labels when you have fit a StringEncoder on one dataset and then use it to transform another: put unseen labels in a special additional bucket, at index is equal amountOfCategories.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected static long	serialVersionUID

Fields inherited from class org.apache.ignite.ml.preprocessing.encoding.EncoderPreprocessor

basePreprocessor, encodingValues, handledIndices, KEY_FOR_NULL_VALUES

Constructor Summary

Constructors

Constructor and Description
StringEncoderPreprocessor(Map<String,Integer>[] encodingValues, IgniteBiFunction<K,V,Object[]> basePreprocessor, Set<Integer> handledIndices) Constructs a new instance of String Encoder preprocessor.

Method Summary

Modifier and Type	Method and Description
Vector	apply(K k, V v) Applies this preprocessor.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.ignite.ml.math.functions.IgniteBiFunction

andThen

Methods inherited from interface java.util.function.BiFunction

andThen

Field Detail

serialVersionUID

protected static final long serialVersionUID

See Also:

Constant Field Values

Constructor Detail

StringEncoderPreprocessor

public StringEncoderPreprocessor(Map<String,Integer>[] encodingValues,
                                 IgniteBiFunction<K,V,Object[]> basePreprocessor,
                                 Set<Integer> handledIndices)

Constructs a new instance of String Encoder preprocessor.

Parameters:

basePreprocessor - Base preprocessor.

handledIndices - Handled indices.

Method Detail

apply

public Vector apply(K k,
                    V v)

Applies this preprocessor.

Parameters:

k - Key.

v - Value.

Returns:

Preprocessed row.