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,LabeledVector>, DeployableObject, IgniteBiFunction<K,V,LabeledVector>, Preprocessor<K,V>

public final class StringEncoderPreprocessor<K,V>
extends EncoderPreprocessor<K,V>
implements DeployableObject

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, Preprocessor<K,V> basePreprocessor, Set<Integer> handledIndices) Constructs a new instance of String Encoder preprocessor.

Method Summary

Modifier and Type	Method and Description
LabeledVector	apply(K k, V v) Applies this preprocessor.
List<Object>	getDependencies() Returns dependencies of this object that can be object with class defined by client side and unknown for server.

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.preprocessing.Preprocessor

map

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,
                                 Preprocessor<K,V> basePreprocessor,
                                 Set<Integer> handledIndices)

Constructs a new instance of String Encoder preprocessor.

Parameters:

basePreprocessor - Base preprocessor.

handledIndices - Handled indices.

Method Detail

apply

public LabeledVector apply(K k,
                           V v)

Applies this preprocessor.

Specified by:

apply in interface BiFunction<K,V,LabeledVector>

Parameters:

k - Key.

v - Value.

Returns:

Preprocessed row.

getDependencies

public List<Object> getDependencies()

Returns dependencies of this object that can be object with class defined by client side and unknown for server.

Specified by:

getDependencies in interface DeployableObject