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Class weka.filters.InstanceFilter

java.lang.Object
   |
   +----weka.filters.Filter
           |
           +----weka.filters.InstanceFilter

public class InstanceFilter

extends Filter

implements OptionHandler

Valid filter-specific options are:

-C num
Choose attribute to be used for selection (default last).

-S num
Numeric value to be used for selection on numeric attribute. (Instances with values smaller than given value.)

-L index1,index2-index4,...
Range of label indices to be used for selection on nominal attribute. (First and last are valid indexes.)

-V
Invert matching sense.

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

Version:

$Revision: 1.3 $

Author:

Eibe Frank (eibe@cs.waikato.ac.nz)

InstanceFilter()

getAttributeIndex()

Get the attribute to be used for selection (-1 for last)

getInvertSelection()

Get whether the supplied columns are to be removed or kept

getModifyHeader()

Gets whether the header will be modified when selecting on nominal attributes.

getNominalIndices()

Get the set of nominal value indices that will be used for selection

getOptions()

Gets the current settings of the filter.

getSplitPoint()

Get the split point used for numeric selection

input(Instance)

Input an instance for filtering.

inputFormat(Instances)

Sets the format of the input instances.

isNominal()

Returns true if selection attribute is nominal.

isNumeric()

Returns true if selection attribute is numeric.

listOptions()

Returns an enumeration describing the available options

main(String[])

Main method for testing this class.

setAttributeIndex(int)

Sets attribute to be used for selection

setInvertSelection(boolean)

Set whether selected values should be removed or kept.

setModifyHeader(boolean)

Sets whether the header will be modified when selecting on nominal attributes.

setNominalIndices(String)

Set which nominal labels are to be included in the selection.

setNominalIndicesArr(int[])

Set which values of a nominal attribute are to be used for selection.

setOptions(String[])

Parses a given list of options.

setSplitPoint(double)

Split point to be used for selection on numeric attribute.

 public InstanceFilter()

 public Enumeration listOptions()

Returns an enumeration describing the available options

Returns:

an enumeration of all the available options

 public void setOptions(String options[]) throws Exception

Parses a given list of options. Valid options are:

-C num
Choose attribute to be used for selection (default last).

-S num
Numeric value to be used for selection on numeric attribute. (Instances with values smaller than given value.)

-L index1,index2-index4,...
Range of label indices to be used for selection on nominal attribute. (First and last are valid indexes.)

-V
Invert matching sense.

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

Parameters:

options - the list of options as an array of strings

Throws: Exception

if an option is not supported

 public String[] getOptions()

Gets the current settings of the filter.

Returns:

an array of strings suitable for passing to setOptions

 public boolean inputFormat(Instances instanceInfo) throws Exception

Sets the format of the input instances.

Parameters:

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

Throws: Exception

if selection is not possible

Overrides:

inputFormat in class Filter

 public boolean input(Instance instance) throws 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.

Parameters:

instance - the input instance

Returns:

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

Throws: Exception

if the input instance was not of the correct format or if there was a problem with the filtering.

Overrides:

input in class Filter

 public boolean isNominal()

Returns true if selection attribute is nominal.

Returns:

true if selection attribute is nominal

 public boolean isNumeric()

Returns true if selection attribute is numeric.

Returns:

true if selection attribute is numeric

 public boolean getModifyHeader()

Gets whether the header will be modified when selecting on nominal attributes.

Returns:

true if so.

 public void setModifyHeader(boolean newModifyHeader)

Sets whether the header will be modified when selecting on nominal attributes.

Parameters:

newModifyHeader - true if so.

 public int getAttributeIndex()

Get the attribute to be used for selection (-1 for last)

Returns:

the attribute index

 public void setAttributeIndex(int attribute)

Sets attribute to be used for selection

Parameters:

attribute - the attribute's index (-1 for last);

 public double getSplitPoint()

Get the split point used for numeric selection

Returns:

the numeric split point

 public void setSplitPoint(double value)

Split point to be used for selection on numeric attribute.

Parameters:

value - the split point

 public boolean getInvertSelection()

Get whether the supplied columns are to be removed or kept

Returns:

true if the supplied columns will be kept

 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

 public String getNominalIndices()

Get the set of nominal value indices that will be used for selection

Returns:

rangeList a string representing the list of nominal indices.

 public void setNominalIndices(String rangeList) throws Exception

Set which nominal labels are to be included in the selection.

Parameters:

rangeList - a string representing the list of nominal indices. eg: first-3,5,6-last

Throws: Exception

if an invalid range list is supplied

 public void setNominalIndicesArr(int values[]) throws Exception

Set which values of a nominal attribute are to be used for selection.

Parameters:

values - an array containing indexes of values to be used for selection

Throws: Exception

if an invalid set of ranges is supplied

 public static void main(String argv[])

Main method for testing this class.

Parameters:

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

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