Class AddExpression
- java.lang.Object
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- weka.filters.Filter
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- weka.filters.unsupervised.attribute.AddExpression
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- All Implemented Interfaces:
java.io.Serializable
,CapabilitiesHandler
,OptionHandler
,RevisionHandler
,StreamableFilter
,UnsupervisedFilter
public class AddExpression extends Filter implements UnsupervisedFilter, StreamableFilter, OptionHandler
An instance filter that creates a new attribute by applying a mathematical expression to existing attributes. The expression can contain attribute references and numeric constants. Supported operators are :
+, -, *, /, ^, log, abs, cos, exp, sqrt, floor, ceil, rint, tan, sin, (, )
Attributes are specified by prefixing with 'a', eg. a7 is attribute number 7 (starting from 1).
Example expression : a1^2*a5/log(a7*4.0). Valid options are:-E <expression> Specify the expression to apply. Eg a1^2*a5/log(a7*4.0). Supported opperators: ,+, -, *, /, ^, log, abs, cos, exp, sqrt, floor, ceil, rint, tan, sin, (, ) (default: a1^2)
-N <name> Specify the name for the new attribute. (default is the expression provided with -E)
-D Debug. Names attribute with the postfix parse of the expression.
- Version:
- $Revision: 5543 $
- Author:
- Mark Hall (mhall@cs.waikato.ac.nz)
- See Also:
- Serialized Form
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Constructor Summary
Constructors Constructor Description AddExpression()
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description java.lang.String
debugTipText()
Returns the tip text for this propertyjava.lang.String
expressionTipText()
Returns the tip text for this propertyCapabilities
getCapabilities()
Returns the Capabilities of this filter.boolean
getDebug()
Gets whether debug is setjava.lang.String
getExpression()
Get the expressionjava.lang.String
getName()
Returns the name of the new attributejava.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 filterboolean
input(Instance instance)
Input an instance for filtering.java.util.Enumeration
listOptions()
Returns an enumeration describing the available options.static void
main(java.lang.String[] args)
Main method for testing this class.java.lang.String
nameTipText()
Returns the tip text for this propertyvoid
setDebug(boolean d)
Set debug mode.void
setExpression(java.lang.String expr)
Set the expression to applyboolean
setInputFormat(Instances instanceInfo)
Sets the format of the input instances.void
setName(java.lang.String name)
Set the name for the new attribute.void
setOptions(java.lang.String[] options)
Parses a given list of options.-
Methods inherited from class weka.filters.Filter
batchFilterFile, batchFinished, filterFile, getCapabilities, getOutputFormat, isFirstBatchDone, isNewBatch, isOutputFormatDefined, makeCopies, makeCopy, numPendingOutput, output, outputPeek, toString, useFilter, wekaStaticWrapper
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Method Detail
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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
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listOptions
public java.util.Enumeration listOptions()
Returns an enumeration describing the available options.- Specified by:
listOptions
in interfaceOptionHandler
- Returns:
- an enumeration of all the available options.
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setOptions
public void setOptions(java.lang.String[] options) throws java.lang.Exception
Parses a given list of options. Valid options are:-E <expression> Specify the expression to apply. Eg a1^2*a5/log(a7*4.0). Supported opperators: ,+, -, *, /, ^, log, abs, cos, exp, sqrt, floor, ceil, rint, tan, sin, (, ) (default: a1^2)
-N <name> Specify the name for the new attribute. (default is the expression provided with -E)
-D Debug. Names attribute with the postfix parse of the expression.
- Specified by:
setOptions
in interfaceOptionHandler
- Parameters:
options
- the list of options as an array of strings- Throws:
java.lang.Exception
- if an option is not supported
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getOptions
public java.lang.String[] getOptions()
Gets the current settings of the filter.- Specified by:
getOptions
in interfaceOptionHandler
- Returns:
- an array of strings suitable for passing to setOptions
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nameTipText
public java.lang.String nameTipText()
Returns the tip text for this property- Returns:
- tip text for this property suitable for displaying in the explorer/experimenter gui
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setName
public void setName(java.lang.String name)
Set the name for the new attribute. The string "expression" can be used to make the name of the new attribute equal to the expression provided.- Parameters:
name
- the name of the new attribute
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getName
public java.lang.String getName()
Returns the name of the new attribute- Returns:
- the name of the new attribute
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debugTipText
public java.lang.String debugTipText()
Returns the tip text for this property- Returns:
- tip text for this property suitable for displaying in the explorer/experimenter gui
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setDebug
public void setDebug(boolean d)
Set debug mode. Causes the new attribute to be named with the postfix parse of the expression- Parameters:
d
- true if debug mode is to be used
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getDebug
public boolean getDebug()
Gets whether debug is set- Returns:
- true if debug is set
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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
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setExpression
public void setExpression(java.lang.String expr)
Set the expression to apply- Parameters:
expr
- a mathematical expression to apply
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getExpression
public java.lang.String getExpression()
Get the expression- Returns:
- the expression
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getCapabilities
public Capabilities getCapabilities()
Returns the Capabilities of this filter.- Specified by:
getCapabilities
in interfaceCapabilitiesHandler
- Overrides:
getCapabilities
in classFilter
- Returns:
- the capabilities of this object
- See Also:
Capabilities
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setInputFormat
public boolean setInputFormat(Instances instanceInfo) throws java.lang.Exception
Sets the format of the input instances.- Overrides:
setInputFormat
in classFilter
- 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 may be collected immediately
- Throws:
java.lang.Exception
- if the format couldn't be set successfully
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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.
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getRevision
public java.lang.String getRevision()
Returns the revision string.- Specified by:
getRevision
in interfaceRevisionHandler
- Overrides:
getRevision
in classFilter
- Returns:
- the revision
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main
public static void main(java.lang.String[] args)
Main method for testing this class.- Parameters:
args
- should contain arguments to the filter: use -h for help
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