weka.core

Class InstanceComparator

java.lang.Object

weka.core.InstanceComparator

All Implemented Interfaces:

Serializable, Comparator<Instance>, RevisionHandler

public class InstanceComparator
extends Object
implements Comparator<Instance>, Serializable, RevisionHandler

A comparator for the Instance class. it can be used with or without the class label. Missing values are sorted at the beginning.
Can be used as comparator in the sorting and binary search algorithms of Arrays and Collections. Relational values are compared instance by instance with a nested InstanceComparator.

Version:

$Revision: 8034 $

Author:

FracPete (fracpete at cs dot waikato dot ac dot nz)

See Also:

Instance, Arrays, Collections, Serialized Form

Constructor Summary

Constructors

Constructor and Description
InstanceComparator() Initializes the comparator and includes the class in the comparison and all attributes included.
InstanceComparator(boolean includeClass) Initializes the comparator with all attributes included.
InstanceComparator(boolean includeClass, String range, boolean invert) Initializes the comparator.

Method Summary

Methods

Modifier and Type	Method and Description
int	compare(Instance inst1, Instance inst2) compares the two instances, returns -1 if o1 is smaller than o2, 0 if equal and +1 if greater.
boolean	getIncludeClass() Returns whether the class is included in the comparison.
boolean	getInvert() Returns whether the matching sense of the attribute range is inverted.
String	getRange() Returns the attribute range to use in the comparison.
String	getRevision() Returns the revision string.
static void	main(String[] args) for testing only.
void	setIncludeClass(boolean includeClass) Sets whether the class should be included in the comparison.
void	setInvert(boolean value) Sets whether to invert the matching sense of the attribute range.
void	setRange(String value) Sets the attribute range to use for comparison.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Comparator

equals

Constructor Detail

InstanceComparator

public InstanceComparator()

Initializes the comparator and includes the class in the comparison and all attributes included.

InstanceComparator

public InstanceComparator(boolean includeClass)

Initializes the comparator with all attributes included.

Parameters:

includeClass - whether to include the class in the comparison

InstanceComparator

public InstanceComparator(boolean includeClass,
                  String range,
                  boolean invert)

Initializes the comparator.

Parameters:

includeClass - whether to include the class in the comparison

range - the attribute range string

inverted - whether to invert the matching sense of the att range

Method Detail

setIncludeClass

public void setIncludeClass(boolean includeClass)

Sets whether the class should be included in the comparison.

Parameters:

includeClass - true if to include the class in the comparison

getIncludeClass

public boolean getIncludeClass()

Returns whether the class is included in the comparison.

Returns:

true if the class is included

setRange

public void setRange(String value)

Sets the attribute range to use for comparison.

Parameters:

value - the attribute range

getRange

public String getRange()

Returns the attribute range to use in the comparison.

Returns:

the attribute range

setInvert

public void setInvert(boolean value)

Sets whether to invert the matching sense of the attribute range.

Parameters:

invert - true if to invert the matching sense

getInvert

public boolean getInvert()

Returns whether the matching sense of the attribute range is inverted.

Returns:

true if the matching sense is inverted

compare

public int compare(Instance inst1,
          Instance inst2)

compares the two instances, returns -1 if o1 is smaller than o2, 0 if equal and +1 if greater. The method assumes that both instance objects have the same attributes, they don't have to belong to the same dataset.

Specified by:

compare in interface Comparator<Instance>

Parameters:

inst1 - the first instance to compare

inst2 - the second instance to compare

Returns:

returns -1 if inst1 is smaller than inst2, 0 if equal and +1 if greater

getRevision

public String getRevision()

Returns the revision string.

Specified by:

getRevision in interface RevisionHandler

Returns:

the revision

main

public static void main(String[] args)
                 throws Exception

for testing only. takes an ARFF-filename as first argument to perform some tests.

Throws:

Exception