weka.core

Class InstanceComparator

java.lang.Object

weka.core.InstanceComparator

All Implemented Interfaces:

Serializable, Comparator, RevisionHandler

public class InstanceComparator
extends Object
implements Comparator, 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: 7988 $

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
InstanceComparator(boolean includeClass) initializes the comparator

Method Summary

Modifier and Type	Method and Description
int	compare(Object o1, Object o2) compares the two instances, returns -1 if o1 is smaller than o2, 0 if equal and +1 if greater.
boolean	getIncludeClass() returns TRUE if the class is included 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 (= TRUE) in the comparison

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Comparator

comparing, comparing, comparingDouble, comparingInt, comparingLong, equals, naturalOrder, nullsFirst, nullsLast, reversed, reverseOrder, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

Constructor Detail

InstanceComparator

public InstanceComparator()

initializes the comparator and includes the class in the comparison

InstanceComparator

public InstanceComparator(boolean includeClass)

initializes the comparator

Method Detail

setIncludeClass

public void setIncludeClass(boolean includeClass)

sets whether the class should be included (= TRUE) in the comparison

Parameters:

includeClass - whether to include the class in the comparison

getIncludeClass

public boolean getIncludeClass()

returns TRUE if the class is included in the comparison

compare

public int compare(Object o1,
                   Object o2)

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

Parameters:

o1 - the first instance to compare

o2 - the second instance to compare

Returns:

returns -1 if o1 is smaller than o2, 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