org.datavec.api.transform.transform.categorical

Class PivotTransform

java.lang.Object

org.datavec.api.transform.transform.BaseTransform

org.datavec.api.transform.transform.categorical.PivotTransform

All Implemented Interfaces:

Serializable, ColumnOp, Transform

public class PivotTransform
extends BaseTransform

Pivot transform operates on two columns: - a categorical column that operates as a key, and - Another column that contains a value Essentially, Pivot transform takes keyvalue pairs and breaks them out into separate columns. For example, with schema [col0, key, value, col3] and values with key in {a,b,c} Output schema is [col0, key[a], key[b], key[c], col3] and input (col0Val, b, x, col3Val) gets mapped to (col0Val, 0, x, 0, col3Val). When expanding columns, a default value is used - for example 0 for numerical columns.

Author:

Alex Black

See Also:

Serialized Form

Field Summary

Fields inherited from class org.datavec.api.transform.transform.BaseTransform

inputSchema

Constructor Summary

Constructors

Constructor and Description
PivotTransform(String keyColumnName, String valueColumnName)
PivotTransform(String keyColumnName, String valueColumnName, Writable defaultValue)

Method Summary

Modifier and Type	Method and Description
String	columnName() Returns a singular column name this op is meant to run on
String[]	columnNames() Returns column names this op is meant to run on
List<Writable>	map(List<Writable> writables) Transform a writable in to another writable
Object	map(Object input) Transform an object in to another object
Object	mapSequence(Object sequence) Transform a sequence
String	outputColumnName() The output column name after the operation has been applied
String[]	outputColumnNames() The output column names This will often be the same as the input
Schema	transform(Schema inputSchema) Get the output schema for this transformation, given an input schema

Methods inherited from class org.datavec.api.transform.transform.BaseTransform

getInputSchema, mapSequence, setInputSchema, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

PivotTransform

public PivotTransform(String keyColumnName,
                      String valueColumnName)

Parameters:

keyColumnName - Key column to expand

valueColumnName - Name of the column that contains the value

PivotTransform

public PivotTransform(String keyColumnName,
                      String valueColumnName,
                      Writable defaultValue)

Parameters:

keyColumnName - Key column to expand

valueColumnName - Name of the column that contains the value

defaultValue - The default value to use in expanded columns.

Method Detail

transform

public Schema transform(Schema inputSchema)

Description copied from interface: ColumnOp

Get the output schema for this transformation, given an input schema

outputColumnName

public String outputColumnName()

Description copied from interface: ColumnOp

The output column name after the operation has been applied

Returns:

the output column name

outputColumnNames

public String[] outputColumnNames()

Description copied from interface: ColumnOp

The output column names This will often be the same as the input

Returns:

the output column names

columnNames

public String[] columnNames()

Description copied from interface: ColumnOp

Returns column names this op is meant to run on

Returns:

columnName

public String columnName()

Description copied from interface: ColumnOp

Returns a singular column name this op is meant to run on

Returns:

map

public List<Writable> map(List<Writable> writables)

Description copied from interface: Transform

Transform a writable in to another writable

Parameters:

writables - the record to transform

Returns:

the transformed writable

map

public Object map(Object input)

Description copied from interface: Transform

Transform an object in to another object

Parameters:

input - the record to transform

Returns:

the transformed writable

mapSequence

public Object mapSequence(Object sequence)

Description copied from interface: Transform

Transform a sequence