Package weka.filters.supervised.attribute

Class MergeNominalValues

  • All Implemented Interfaces:
    java.io.Serializable, CapabilitiesHandler, CapabilitiesIgnorer, CommandlineRunnable, OptionHandler, RevisionHandler, TechnicalInformationHandler, WeightedAttributesHandler, WeightedInstancesHandler, SupervisedFilter
    public class MergeNominalValues
extends SimpleBatchFilter
implements SupervisedFilter, WeightedInstancesHandler, WeightedAttributesHandler, TechnicalInformationHandler
    Merges values of all nominal attributes among the specified attributes, excluding the class attribute, using the CHAID method, but without considering re-splitting of merged subsets. It implements Steps 1 and 2 described by Kass (1980), see

    Gordon V. Kass (1980). An Exploratory Technique for Investigating Large Quantities of Categorical Data. Applied Statistics. 29(2):119-127.

    Once attribute values have been merged, a chi-squared test using the Bonferroni correction is applied to check if the resulting attribute is a valid predictor, based on the Bonferroni multiplier in Equation 3.2 in Kass (1980). If an attribute does not pass this test, all remaining values (if any) are merged. Nevertheless, useless predictors can slip through without being fully merged, e.g. identifier attributes.

    The code applies the Yates correction when the chi-squared statistic is computed.

    Note that the algorithm is quadratic in the number of attribute values for an attribute.

    Valid options are: 

     -D
  Turns on output of debugging information.
 
     -L <double>
  The significance level (default: 0.05).
 
     -R <range>
  Sets list of attributes to act on (or its inverse). 'first and 'last' are accepted as well.'
  E.g.: first-5,7,9,20-last
  (default: first-last)
 
     -V
  Invert matching sense (i.e. act on all attributes not specified in list)
 
     -O
  Use short identifiers for merged subsets.
    Version:
    $Revision: 14534 $
    Author:
    Eibe Frank
    See Also:
    Serialized Form

    • Constructor Detail

      • MergeNominalValues

        public MergeNominalValues()

    • Method Detail

      • globalInfo

        public java.lang.String globalInfo()
        Returns a string describing this filter.
        Specified by:
        globalInfo in class SimpleFilter
        Returns:
        a description of the filter suitable for displaying in the explorer/experimenter gui

      • getTechnicalInformation

        public TechnicalInformation getTechnicalInformation()
        Returns an instance of a TechnicalInformation object, containing detailed information about the technical background of this class, e.g., paper reference or book this class is based on.
        Specified by:
        getTechnicalInformation in interface TechnicalInformationHandler
        Returns:
        the technical information about this class

      • 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.

      • 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

      • setOptions

        public void setOptions​(java.lang.String[] options)
                throws java.lang.Exception
        Parses a given list of options.

        Valid options are: 

         -D
  Turns on output of debugging information.
 
         -L <double>
  The significance level (default: 0.05).
 
         -R <range>
  Sets list of attributes to act on (or its inverse). 'first and 'last' are accepted as well.'
  E.g.: first-5,7,9,20-last
  (default: first-last)
 
         -V
  Invert matching sense (i.e. act on all attributes not specified in list)
 
         -O
  Use short identifiers for merged subsets.
        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

      • significanceLevelTipText

        public java.lang.String significanceLevelTipText()
        Returns the tip text for this property
        Returns:
        tip text for this property suitable for displaying in the explorer/experimenter gui

      • getSignificanceLevel

        public double getSignificanceLevel()
        Gets the significance level.
        Returns:
        int the significance level.

      • setSignificanceLevel

        public void setSignificanceLevel​(double sF)
        Sets the significance level.
        Parameters:
        sF - the significance level as a double.

      • attributeIndicesTipText

        public java.lang.String attributeIndicesTipText()
        Returns the tip text for this property
        Returns:
        tip text for this property suitable for displaying in the explorer/experimenter gui

      • getAttributeIndices

        public java.lang.String getAttributeIndices()
        Get the current range selection.
        Returns:
        a string containing a comma separated list of ranges

      • setAttributeIndices

        public void setAttributeIndices​(java.lang.String rangeList)
        Set which attributes are to be acted on (or not, if invert is true)
        Parameters:
        rangeList - a string representing the list of attributes. Since the string will typically come from a user, attributes are indexed from 1.
        eg: first-3,5,6-last

      • setAttributeIndicesArray

        public void setAttributeIndicesArray​(int[] attributes)
        Set which attributes are to be acted on (or not, if invert is true)
        Parameters:
        attributes - an array containing indexes of attributes to select. Since the array will typically come from a program, attributes are indexed from 0.

      • invertSelectionTipText

        public java.lang.String invertSelectionTipText()
        Returns the tip text for this property
        Returns:
        tip text for this property suitable for displaying in the explorer/experimenter gui

      • getInvertSelection

        public boolean getInvertSelection()
        Get whether the supplied attributes are to be acted on or all other attributes.
        Returns:
        true if the supplied attributes will be kept

      • setInvertSelection

        public void setInvertSelection​(boolean invert)
        Set whether selected attributes should be acted on or all other attributes.
        Parameters:
        invert - the new invert setting

      • useShortIdentifiersTipText

        public java.lang.String useShortIdentifiersTipText()
        Returns the tip text for this property
        Returns:
        tip text for this property suitable for displaying in the explorer/experimenter gui

      • getUseShortIdentifiers

        public boolean getUseShortIdentifiers()
        Get whether short identifiers are to be output.
        Returns:
        true if short IDs are output

      • setUseShortIdentifiers

        public void setUseShortIdentifiers​(boolean b)
        Set whether to output short identifiers for merged values.
        Parameters:
        b - if true, short IDs are output

      • allowAccessToFullInputFormat

        public boolean allowAccessToFullInputFormat()
        We need access to the full input data in determineOutputFormat.
        Overrides:
        allowAccessToFullInputFormat in class SimpleBatchFilter
        Returns:
        whether determineOutputFormat has access to the full input dataset

      • main

        public static void main​(java.lang.String[] args)
        runs the filter with the given arguments
        Parameters:
        args - the commandline arguments