weka.filters.unsupervised.instance

## Class RemoveFrequentValues

- java.lang.Object
- - weka.filters.Filter
  - - weka.filters.unsupervised.instance.RemoveFrequentValues

- All Implemented Interfaces:
    java.io.Serializable, CapabilitiesHandler, CapabilitiesIgnorer, OptionHandler, RevisionHandler, UnsupervisedFilter

      public class RemoveFrequentValues
      extends Filter
      implements OptionHandler, UnsupervisedFilter

  Determines which values (frequent or infrequent ones) of an (nominal) attribute are retained and filters the instances accordingly. In case of values with the same frequency, they are kept in the way they appear in the original instances object. E.g. if you have the values "1,2,3,4" with the frequencies "10,5,5,3" and you chose to keep the 2 most common values, the values "1,2" would be returned, since the value "2" comes before "3", even though they have the same frequency.

  Valid options are:

       -C <num>
        Choose attribute to be used for selection.

       -N <num>
        Number of values to retain for the sepcified attribute,
        i.e. the ones with the most instances (default 2).

       -L
        Instead of values with the most instances the ones with the
        least are retained.

       -H
        When selecting on nominal attributes, removes header
        references to excluded values.

       -V
        Invert matching sense.

  Version:
    $Revision: 10649 $
  Author:
    FracPete (fracpete at waikato dot ac dot nz)
  See Also:
    Serialized Form

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `RemoveFrequentValues()`

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `java.lang.String` | `attributeIndexTipText()` Returns the tip text for this property
    `boolean` | `batchFinished()` Signifies that this batch of input to the filter is finished.
    `void` | `determineValues(Instances inst)` determines the values to retain, it is always at least 1 and up to the maximum number of distinct values
    `java.lang.String` | `getAttributeIndex()` Get the index of the attribute used.
    `Capabilities` | `getCapabilities()` Returns the Capabilities of this filter.
    `boolean` | `getInvertSelection()` Get whether the supplied columns are to be removed or kept
    `boolean` | `getModifyHeader()` Gets whether the header will be modified when selecting on nominal attributes.
    `int` | `getNumValues()` Gets how many values are retained
    `java.lang.String[]` | `getOptions()` Gets the current settings of the filter.
    `java.lang.String` | `getRevision()` Returns the revision string.
    `boolean` | `getUseLeastValues()` Gets whether to use values with least or most instances
    `java.lang.String` | `globalInfo()` Returns a string describing this filter
    `boolean` | `input(Instance instance)` Input an instance for filtering.
    `java.lang.String` | `invertSelectionTipText()` Returns the tip text for this property
    `boolean` | `isNominal()` Returns true if selection attribute is nominal.
    `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` | `modifyHeaderTipText()` Returns the tip text for this property
    `java.lang.String` | `numValuesTipText()` Returns the tip text for this property
    `void` | `setAttributeIndex(java.lang.String attIndex)` Sets index of the attribute used.
    `boolean` | `setInputFormat(Instances instanceInfo)` Sets the format of the input instances.
    `void` | `setInvertSelection(boolean invert)` Set whether selected values should be removed or kept.
    `void` | `setModifyHeader(boolean newModifyHeader)` Sets whether the header will be modified when selecting on nominal attributes.
    `void` | `setNumValues(int numValues)` Sets how many values are retained
    `void` | `setOptions(java.lang.String[] options)` Parses a given list of options.
    `void` | `setUseLeastValues(boolean leastValues)` Sets whether to use values with least or most instances
    `java.lang.String` | `useLeastValuesTipText()` Returns the tip text for this property

    - ### Methods inherited from class weka.filters.Filter

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

    - ### Methods inherited from class java.lang.Object

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

- - ### Constructor Detail

    - #### RemoveFrequentValues

          public RemoveFrequentValues()

  - ### Method Detail

    - #### globalInfo

          public java.lang.String globalInfo()

      Returns a string describing this filter
      Returns:
        a description of the classifier suitable for displaying in the explorer/experimenter gui

    - #### 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:

           -C <num>
            Choose attribute to be used for selection.

           -N <num>
            Number of values to retain for the sepcified attribute,
            i.e. the ones with the most instances (default 2).

           -L
            Instead of values with the most instances the ones with the
            least are retained.

           -H
            When selecting on nominal attributes, removes header
            references to excluded values.

           -V
            Invert matching sense.

      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

    - #### attributeIndexTipText

          public java.lang.String attributeIndexTipText()

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

    - #### getAttributeIndex

          public java.lang.String getAttributeIndex()

      Get the index of the attribute used.
      Returns:
        the index of the attribute

    - #### setAttributeIndex

          public void setAttributeIndex(java.lang.String attIndex)

      Sets index of the attribute used.
      Parameters:
        `attIndex` - the index of the attribute

    - #### numValuesTipText

          public java.lang.String numValuesTipText()

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

    - #### getNumValues

          public int getNumValues()

      Gets how many values are retained
      Returns:
        how many values are retained

    - #### setNumValues

          public void setNumValues(int numValues)

      Sets how many values are retained
      Parameters:
        `numValues` - the number of values to retain

    - #### useLeastValuesTipText

          public java.lang.String useLeastValuesTipText()

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

    - #### getUseLeastValues

          public boolean getUseLeastValues()

      Gets whether to use values with least or most instances
      Returns:
        true if values with least instances are retained

    - #### setUseLeastValues

          public void setUseLeastValues(boolean leastValues)

      Sets whether to use values with least or most instances
      Parameters:
        `leastValues` - whether values with least or most instances are retained

    - #### modifyHeaderTipText

          public java.lang.String modifyHeaderTipText()

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

    - #### getModifyHeader

          public boolean getModifyHeader()

      Gets whether the header will be modified when selecting on nominal attributes.
      Returns:
        true if so.

    - #### setModifyHeader

          public void setModifyHeader(boolean newModifyHeader)

      Sets whether the header will be modified when selecting on nominal attributes.
      Parameters:
        `newModifyHeader` - true if so.

    - #### 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 columns are to be removed or kept
      Returns:
        true if the supplied columns will be kept

    - #### setInvertSelection

          public void setInvertSelection(boolean invert)

      Set whether selected values should be removed or kept. If true the selected values are kept and unselected values are deleted.
      Parameters:
        `invert` - the new invert setting

    - #### isNominal

          public boolean isNominal()

      Returns true if selection attribute is nominal.
      Returns:
        true if selection attribute is nominal

    - #### determineValues

          public void determineValues(Instances inst)

      determines the values to retain, it is always at least 1 and up to the maximum number of distinct values
      Parameters:
        `inst` - the Instances to determine the values from which are kept

    - #### 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 can be collected immediately
      Throws:
        `UnsupportedAttributeTypeException` - if the specified attribute is not nominal.
        `java.lang.Exception` - if the inputFormat can't be set successfully

    - #### input

          public boolean input(Instance instance)

      Input an instance for filtering. Ordinarily the instance is processed and made available for output immediately. Some filters require all instances be read before producing output.
      Overrides:
        `input` in class `Filter`
      Parameters:
        `instance` - the input instance
      Returns:
        true if the filtered instance may now be collected with output().
      Throws:
        `java.lang.IllegalStateException` - if no input format has been set.

    - #### batchFinished

          public boolean batchFinished()

      Signifies that this batch of input to the filter is finished. If the filter requires all instances prior to filtering, output() may now be called to retrieve the filtered instances.
      Overrides:
        `batchFinished` in class `Filter`
      Returns:
        true if there are instances pending output
      Throws:
        `java.lang.IllegalStateException` - if no input structure has been defined

    - #### 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