weka.filters.unsupervised.attribute

Class RemoveUseless

java.lang.Object

weka.filters.Filter

weka.filters.unsupervised.attribute.RemoveUseless

All Implemented Interfaces:

java.io.Serializable, CapabilitiesHandler, CapabilitiesIgnorer, CommandlineRunnable, OptionHandler, RevisionHandler, WeightedAttributesHandler, WeightedInstancesHandler, UnsupervisedFilter

public class RemoveUseless
extends Filter
implements UnsupervisedFilter, OptionHandler, WeightedInstancesHandler, WeightedAttributesHandler

This filter removes attributes that do not vary at all or that vary too much. All constant attributes are deleted automatically, along with any that exceed the maximum percentage of variance parameter. The maximum variance test is only applied to nominal attributes.

Valid options are:

 -M <max variance %>
  Maximum variance percentage allowed (default 99). Specifically, if
  (number_of_distinct_values / total_number_of_values * 100)
  is greater than this value, then the attribute will be removed.
 

Version:

$Revision: 14534 $

Author:

Richard Kirkby (rkirkby@cs.waikato.ac.nz)

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
RemoveUseless()

Method Summary

Modifier and Type	Method and Description
boolean	batchFinished() Signify that this batch of input to the filter is finished.
Capabilities	getCapabilities() Returns the Capabilities of this filter.
double	getMaximumVariancePercentageAllowed() Gets the maximum variance attributes are allowed to have before they are deleted by the filter.
java.lang.String[]	getOptions() Gets the current settings of the filter.
java.lang.String	getRevision() Returns the revision string.
java.lang.String	globalInfo() Returns a string describing this filter
boolean	input(Instance instance) Input an instance for filtering.
java.util.Enumeration<Option>	listOptions() Returns an enumeration describing the available options.
static void	main(java.lang.String[] argv) Main method for testing this class.
java.lang.String	maximumVariancePercentageAllowedTipText() Returns the tip text for this property
boolean	setInputFormat(Instances instanceInfo) Sets the format of the input instances.
void	setMaximumVariancePercentageAllowed(double maxVariance) Sets the maximum variance attributes are allowed to have before they are deleted by the filter.
void	setOptions(java.lang.String[] options) Parses a given list of options.

Methods inherited from class weka.filters.Filter

batchFilterFile, debugTipText, doNotCheckCapabilitiesTipText, filterFile, getCapabilities, getCopyOfInputFormat, getDebug, getDoNotCheckCapabilities, getOutputFormat, isFirstBatchDone, isNewBatch, isOutputFormatDefined, makeCopies, makeCopy, mayRemoveInstanceAfterFirstBatchDone, numPendingOutput, output, outputPeek, postExecution, preExecution, run, runFilter, setDebug, setDoNotCheckCapabilities, toString, useFilter, wekaStaticWrapper

Methods inherited from class java.lang.Object

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

Methods inherited from interface weka.core.OptionHandler

makeCopy

Constructor Detail

RemoveUseless

public RemoveUseless()

Method Detail

getCapabilities

public Capabilities getCapabilities()

Returns the Capabilities of this filter.

Specified by:

getCapabilities in interface CapabilitiesHandler

Overrides:

getCapabilities in class Filter

Returns:

the capabilities of this object

See Also:

Capabilities

setInputFormat

public boolean setInputFormat(Instances instanceInfo)
                       throws java.lang.Exception

Sets the format of the input instances.

Overrides:

setInputFormat in class Filter

Parameters:

instanceInfo - an Instances object containing the input instance structure (any instances contained in the object are ignored - only the structure is required).

Returns:

true if the outputFormat may be collected immediately

Throws:

java.lang.Exception - if the inputFormat can't be set successfully

input

public boolean input(Instance instance)

Input an instance for filtering.

Overrides:

input in class Filter

Parameters:

instance - the input instance

Returns:

true if the filtered instance may now be collected with output().

batchFinished

public boolean batchFinished()
                      throws java.lang.Exception

Signify that this batch of input to the filter is finished.

Overrides:

batchFinished in class Filter

Returns:

true if there are instances pending output

Throws:

java.lang.Exception - if no input format defined

listOptions

public java.util.Enumeration<Option> listOptions()

Returns an enumeration describing the available options.

Specified by:

listOptions in interface OptionHandler

Overrides:

listOptions in class Filter

Returns:

an enumeration of all the available options.

setOptions

public void setOptions(java.lang.String[] options)
                throws java.lang.Exception

Parses a given list of options.

Valid options are:

 -M <max variance %>
  Maximum variance percentage allowed (default 99). Specifically, if
  (number_of_distinct_values / total_number_of_values * 100)
  is greater than this value, then the attribute will be removed.
 

Specified by:

setOptions in interface OptionHandler

Overrides:

setOptions in class Filter

Parameters:

options - the list of options as an array of strings

Throws:

java.lang.Exception - if an option is not supported

getOptions

public java.lang.String[] getOptions()

Gets the current settings of the filter.

Specified by:

getOptions in interface OptionHandler

Overrides:

getOptions in class Filter

Returns:

an array of strings suitable for passing to setOptions

globalInfo

public java.lang.String globalInfo()

Returns a string describing this filter

Returns:

a description of the filter suitable for displaying in the explorer/experimenter gui

maximumVariancePercentageAllowedTipText

public java.lang.String maximumVariancePercentageAllowedTipText()

Returns the tip text for this property

Returns:

tip text for this property suitable for displaying in the explorer/experimenter gui

setMaximumVariancePercentageAllowed

public void setMaximumVariancePercentageAllowed(double maxVariance)

Sets the maximum variance attributes are allowed to have before they are deleted by the filter.

Parameters:

maxVariance - the maximum variance allowed, specified as a percentage

getMaximumVariancePercentageAllowed

public double getMaximumVariancePercentageAllowed()

Gets the maximum variance attributes are allowed to have before they are deleted by the filter.

Returns:

the maximum variance allowed, specified as a percentage

getRevision

public java.lang.String getRevision()

Returns the revision string.

Specified by:

getRevision in interface RevisionHandler

Overrides:

getRevision in class Filter

Returns:

the revision

main

public static void main(java.lang.String[] argv)

Main method for testing this class.

Parameters:

argv - should contain arguments to the filter: use -h for help