AddExpression

java.lang.Object
- weka.filters.Filter
- - weka.filters.unsupervised.attribute.AddExpression

All Implemented Interfaces:

java.io.Serializable, CapabilitiesHandler, CapabilitiesIgnorer, CommandlineRunnable, OptionHandler, RevisionHandler, WeightedAttributesHandler, WeightedInstancesHandler, StreamableFilter, UnsupervisedFilter
```
public class AddExpression
extends Filter
implements UnsupervisedFilter, StreamableFilter, OptionHandler, WeightedInstancesHandler, WeightedAttributesHandler
```
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: 0.0)
 
```
```
 -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: 14534 $

Author:

Mark Hall (mhall@cs.waikato.ac.nz)

See Also:

Serialized Form

Constructor Summary

Constructors
Constructor and Description

AddExpression()

Constructors
Constructor and Description
`AddExpression()`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`java.lang.String`	`debugTipText()` Returns the tip text for this property
`java.lang.String`	`expressionTipText()` Returns the tip text for this property
`Capabilities`	`getCapabilities()` Returns the Capabilities of this filter.
`boolean`	`getDebug()` Gets whether debug is set
`java.lang.String`	`getExpression()` Get the expression
`java.lang.String`	`getName()` Returns the name of the new attribute
`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
`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[] args)` Main method for testing this class.
`java.lang.String`	`nameTipText()` Returns the tip text for this property
`void`	`setDebug(boolean d)` Set debug mode.
`void`	`setExpression(java.lang.String expr)` Set the expression to apply
`boolean`	`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 java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface weka.core.OptionHandler
makeCopy

- Constructor Detail
  - AddExpression
```
public AddExpression()
```
- 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:
```
 -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 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
  - 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
  - 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
  - getName
```
public java.lang.String getName()
```
    Returns the name of the new attribute
    
    Returns:
    
    the name of the new attribute
  - debugTipText
```
public java.lang.String debugTipText()
```
    Returns the tip text for this property
    
    Overrides:
    
    debugTipText in class Filter
    
    Returns:
    
    tip text for this property suitable for displaying in the explorer/experimenter gui
  - setDebug
```
public void setDebug(boolean d)
```
    Set debug mode. Causes the new attribute to be named with the postfix parse of the expression
    
    Overrides:
    
    setDebug in class Filter
    
    Parameters:
    
    d - true if debug mode is to be used
  - getDebug
```
public boolean getDebug()
```
    Gets whether debug is set
    
    Overrides:
    
    getDebug in class Filter
    
    Returns:
    
    true if debug is set
  - 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
  - setExpression
```
public void setExpression(java.lang.String expr)
```
    Set the expression to apply
    
    Parameters:
    
    expr - a mathematical expression to apply
  - getExpression
```
public java.lang.String getExpression()
```
    Get the expression
    
    Returns:
    
    the expression
  - 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 may be collected immediately
    
    Throws:
    
    java.lang.Exception - if the format couldn't be set successfully
  - 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 there was a problem during the filtering.
  - 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 testing this class.
    
    Parameters:
    
    args - should contain arguments to the filter: use -h for help

Class AddExpression

Constructor Summary

Method Summary

Methods inherited from class weka.filters.Filter

Methods inherited from class java.lang.Object

Methods inherited from interface weka.core.OptionHandler

Constructor Detail

AddExpression

Method Detail

globalInfo

listOptions

setOptions

getOptions

nameTipText

setName

getName

debugTipText

setDebug

getDebug

expressionTipText

setExpression

getExpression

getCapabilities

setInputFormat

input

getRevision

main