weka.filters.unsupervised.instance

Class SubsetByExpression

java.lang.Object

weka.filters.Filter

weka.filters.SimpleFilter

weka.filters.SimpleBatchFilter

weka.filters.unsupervised.instance.SubsetByExpression

All Implemented Interfaces:

java.io.Serializable, CapabilitiesHandler, OptionHandler, RevisionHandler

public class SubsetByExpression
extends SimpleBatchFilter

Filters instances according to a user-specified expression.

Grammar:

boolexpr_list ::= boolexpr_list boolexpr_part | boolexpr_part;

boolexpr_part ::= boolexpr:e {: parser.setResult(e); :} ;

boolexpr ::= BOOLEAN
| true
| false
| expr < expr
| expr <= expr
| expr > expr
| expr >= expr
| expr = expr
| ( boolexpr )
| not boolexpr
| boolexpr and boolexpr
| boolexpr or boolexpr
| ATTRIBUTE is STRING
;

expr ::= NUMBER
| ATTRIBUTE
| ( expr )
| opexpr
| funcexpr
;

opexpr ::= expr + expr
| expr - expr
| expr * expr
| expr / expr
;

funcexpr ::= abs ( expr )
| sqrt ( expr )
| log ( expr )
| exp ( expr )
| sin ( expr )
| cos ( expr )
| tan ( expr )
| rint ( expr )
| floor ( expr )
| pow ( expr for base , expr for exponent )
| ceil ( expr )
;

Notes:
- NUMBER
any integer or floating point number
(but not in scientific notation!)
- STRING
any string surrounded by single quotes;
the string may not contain a single quote though.
- ATTRIBUTE
the following placeholders are recognized for
attribute values:
- CLASS for the class value in case a class attribute is set.
- ATTxyz with xyz a number from 1 to # of attributes in the
dataset, representing the value of indexed attribute.

Examples:
- extracting only mammals and birds from the 'zoo' UCI dataset:
(CLASS is 'mammal') or (CLASS is 'bird')
- extracting only animals with at least 2 legs from the 'zoo' UCI dataset:
(ATT14 >= 2)
- extracting only instances with non-missing 'wage-increase-second-year'
from the 'labor' UCI dataset:
not ismissing(ATT3)

Valid options are:

 -E <expr>
  The expression to use for filtering
  (default: true).

Version:

$Revision: 6113 $

Author:

fracpete (fracpete at waikato dot ac dot nz)

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
SubsetByExpression()

Method Summary

Methods

Modifier and Type	Method and Description
java.lang.String	expressionTipText() Returns the tip text for this property.
Capabilities	getCapabilities() Returns the Capabilities of this filter.
java.lang.String	getExpression() Returns the expression used for filtering.
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.
java.util.Enumeration	listOptions() Returns an enumeration describing the available options.
static void	main(java.lang.String[] args) Main method for running this filter.
void	setExpression(java.lang.String value) Sets the expression used for filtering.
void	setOptions(java.lang.String[] options) Parses a given list of options.

Methods inherited from class weka.filters.SimpleBatchFilter

batchFinished, input

Methods inherited from class weka.filters.SimpleFilter

debugTipText, getDebug, setDebug, setInputFormat

Methods inherited from class weka.filters.Filter

batchFilterFile, filterFile, getCapabilities, getOutputFormat, isFirstBatchDone, isNewBatch, isOutputFormatDefined, makeCopies, makeCopy, numPendingOutput, output, outputPeek, toString, useFilter, wekaStaticWrapper

Methods inherited from class java.lang.Object

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

Constructor Detail

SubsetByExpression

public SubsetByExpression()

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

listOptions

public java.util.Enumeration listOptions()

Returns an enumeration describing the available options.

Specified by:

listOptions in interface OptionHandler

Overrides:

listOptions in class SimpleFilter

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:

 -E <expr>
  The expression to use for filtering
  (default: true).

Specified by:

setOptions in interface OptionHandler

Overrides:

setOptions in class SimpleFilter

Parameters:

options - the list of options as an array of strings

Throws:

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

See Also:

SimpleFilter.reset()

getOptions

public java.lang.String[] getOptions()

Gets the current settings of the filter.

Specified by:

getOptions in interface OptionHandler

Overrides:

getOptions in class SimpleFilter

Returns:

an array of strings suitable for passing to setOptions

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

setExpression

public void setExpression(java.lang.String value)

Sets the expression used for filtering.

Parameters:

value - the expression

getExpression

public java.lang.String getExpression()

Returns the expression used for filtering.

Returns:

the expression

expressionTipText

public java.lang.String expressionTipText()

Returns the tip text for this property.

Returns:

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

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[] args)

Main method for running this filter.

Parameters:

args - arguments for the filter: use -h for help