org.datavec.api.transform.transform.categorical

Class FirstDigitTransform

java.lang.Object

org.datavec.api.transform.transform.BaseTransform

org.datavec.api.transform.transform.categorical.FirstDigitTransform

All Implemented Interfaces:

Serializable, ColumnOp, Operation<Schema,Schema>, Transform

public class FirstDigitTransform
extends BaseTransform

FirstDigitTransform converts a column to a categorical column, with values being the first digit of the number.
For example, "3.1415" becomes "3" and "2.0" becomes "2".
Negative numbers ignore the sign: "-7.123" becomes "7".
Note that two FirstDigitTransform.Modes are supported, which determines how non-numerical entries should be handled:
EXCEPTION_ON_INVALID: output has 10 category values ("0", ..., "9"), and any non-numerical values result in an exception
INCLUDE_OTHER_CATEGORY: output has 11 category values ("0", ..., "9", "Other"), all non-numerical values are mapped to "Other"

FirstDigitTransform is useful (combined with CategoricalToOneHotTransform and Reductions) to implement Benford's law.

Author:

Alex Black

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	FirstDigitTransform.Mode Mode determines how non-numerical entries should be handled: EXCEPTION_ON_INVALID: output has 10 category values ("0", ..., "9"), and any non-numerical values result in an exception INCLUDE_OTHER_CATEGORY: output has 11 category values ("0", ..., "9", "Other"), all non-numerical values are mapped to "Other"

Field Summary

Fields

Modifier and Type	Field and Description
protected String	inputColumn
protected FirstDigitTransform.Mode	mode
static String	OTHER_CATEGORY
protected String	outputColumn

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

inputSchema

Constructor Summary

Constructors

Constructor and Description
FirstDigitTransform(String inputColumn, String outputColumn, FirstDigitTransform.Mode mode)

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
void	setInputSchema(Schema schema) Set the input schema.
String	toString()
Schema	transform(Schema inputSchema)

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

getInputSchema, mapSequence

Methods inherited from class java.lang.Object

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

Field Detail

OTHER_CATEGORY

public static final String OTHER_CATEGORY

See Also:

Constant Field Values

inputColumn

protected String inputColumn

outputColumn

protected String outputColumn

mode

protected FirstDigitTransform.Mode mode

Constructor Detail

FirstDigitTransform

public FirstDigitTransform(String inputColumn,
                           String outputColumn,
                           FirstDigitTransform.Mode mode)

Parameters:

inputColumn - Input column name

outputColumn - Output column name. If same as input, input column is replaced

mode - See FirstDigitTransform.Mode

Method Detail

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

toString

public String toString()

Specified by:

toString in class BaseTransform

transform

public Schema transform(Schema inputSchema)

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:

setInputSchema

public void setInputSchema(Schema schema)

Description copied from interface: ColumnOp

Set the input schema.

Specified by:

setInputSchema in interface ColumnOp

Overrides:

setInputSchema in class BaseTransform