weka.filters.supervised.attribute

## Class AttributeSelection

- java.lang.Object
- - weka.filters.Filter
  - - weka.filters.supervised.attribute.AttributeSelection

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

      public class AttributeSelection
      extends Filter
      implements SupervisedFilter, OptionHandler

  A supervised attribute filter that can be used to select attributes. It is very flexible and allows various search and evaluation methods to be combined.

  Valid options are:

       -S <"Name of search class [search options]">
        Sets search method for subset evaluators.
        eg. -S "weka.attributeSelection.BestFirst -S 8"

       -E <"Name of attribute/subset evaluation class [evaluator options]">
        Sets attribute/subset evaluator.
        eg. -E "weka.attributeSelection.CfsSubsetEval -L"

       Options specific to evaluator weka.attributeSelection.CfsSubsetEval:

       -M
        Treat missing values as a seperate value.

       -L
        Don't include locally predictive attributes.

       Options specific to search weka.attributeSelection.BestFirst:

       -P <start set>
        Specify a starting set of attributes.
        Eg. 1,3,5-7.

       -D <0 = backward | 1 = forward | 2 = bi-directional>
        Direction of search. (default = 1).

       -N <num>
        Number of non-improving nodes to
        consider before terminating search.

       -S <num>
        Size of lookup cache for evaluated subsets.
        Expressed as a multiple of the number of
        attributes in the data set. (default = 1)

  Version:
    $Revision: 10866 $
  Author:
    Mark Hall (mhall@cs.waikato.ac.nz)
  See Also:
    Serialized Form

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `AttributeSelection()` Constructor

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `boolean` | `batchFinished()` Signify that this batch of input to the filter is finished.
    `java.lang.String` | `evaluatorTipText()` Returns the tip text for this property
    `Capabilities` | `getCapabilities()` Returns the Capabilities of this filter.
    `ASEvaluation` | `getEvaluator()` Get the name of the attribute/subset evaluator
    `java.lang.String[]` | `getOptions()` Gets the current settings for the attribute selection (search, evaluator) etc.
    `java.lang.String` | `getRevision()` Returns the revision string.
    `ASSearch` | `getSearch()` Get the name of the search method
    `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` | `searchTipText()` Returns the tip text for this property
    `void` | `setEvaluator(ASEvaluation evaluator)` set attribute/subset evaluator
    `void` | `setOptions(java.lang.String[] options)` Parses a given list of options.
    `void` | `setSearch(ASSearch search)` Set search class

    - ### 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, setInputFormat, toString, useFilter, wekaStaticWrapper`

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

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

- - ### Constructor Detail

    - #### AttributeSelection

          public AttributeSelection()

      Constructor

  - ### Method Detail

    - #### 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

    - #### 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:

           -S <"Name of search class [search options]">
            Sets search method for subset evaluators.
            eg. -S "weka.attributeSelection.BestFirst -S 8"

           -E <"Name of attribute/subset evaluation class [evaluator options]">
            Sets attribute/subset evaluator.
            eg. -E "weka.attributeSelection.CfsSubsetEval -L"

           Options specific to evaluator weka.attributeSelection.CfsSubsetEval:

           -M
            Treat missing values as a seperate value.

           -L
            Don't include locally predictive attributes.

           Options specific to search weka.attributeSelection.BestFirst:

           -P <start set>
            Specify a starting set of attributes.
            Eg. 1,3,5-7.

           -D <0 = backward | 1 = forward | 2 = bi-directional>
            Direction of search. (default = 1).

           -N <num>
            Number of non-improving nodes to
            consider before terminating search.

           -S <num>
            Size of lookup cache for evaluated subsets.
            Expressed as a multiple of the number of
            attributes in the data set. (default = 1)

      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 for the attribute selection (search, evaluator) etc.
      Specified by:
        `getOptions` in interface `OptionHandler`
      Overrides:
        `getOptions` in class `Filter`
      Returns:
        an array of strings suitable for passing to setOptions()

    - #### evaluatorTipText

          public java.lang.String evaluatorTipText()

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

    - #### setEvaluator

          public void setEvaluator(ASEvaluation evaluator)

      set attribute/subset evaluator
      Parameters:
        `evaluator` - the evaluator to use

    - #### searchTipText

          public java.lang.String searchTipText()

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

    - #### setSearch

          public void setSearch(ASSearch search)

      Set search class
      Parameters:
        `search` - the search class to use

    - #### getEvaluator

          public ASEvaluation getEvaluator()

      Get the name of the attribute/subset evaluator
      Returns:
        the name of the attribute/subset evaluator as a string

    - #### getSearch

          public ASSearch getSearch()

      Get the name of the search method
      Returns:
        the name of the search method as a string

    - #### 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`

    - #### input

          public boolean input(Instance instance)
                        throws java.lang.Exception

      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 defined.
        `java.lang.Exception` - if the input instance was not of the correct format or if there was a problem with the filtering.

    - #### batchFinished

          public boolean batchFinished()
                                throws java.lang.Exception

      Signify 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.
        `java.lang.Exception` - if there is a problem during the attribute selection.

    - #### 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