weka.classifiers.rules

## Class JRip.RipperRule

- java.lang.Object
- - weka.classifiers.rules.Rule
  - - weka.classifiers.rules.JRip.RipperRule

- All Implemented Interfaces:
    java.io.Serializable, Copyable, RevisionHandler, WeightedInstancesHandler
  Enclosing class:
    JRip

      public class JRip.RipperRule
      extends Rule

  This class implements a single rule that predicts specified class. A rule consists of antecedents "AND"ed together and the consequent (class value) for the classification. In this class, the Information Gain (p*[log(p/t) - log(P/T)]) is used to select an antecedent and Reduced Error Prunning (REP) with the metric of accuracy rate p/(p+n) or (TP+TN)/(P+N) is used to prune the rule.
  See Also:
    Serialized Form

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `RipperRule()` Constructor

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `java.lang.Object` | `copy()` Get a shallow copy of this rule
    `boolean` | `covers(Instance datum)` Whether the instance covered by this rule
    `java.util.ArrayList<JRip.Antd>` | `getAntds()` Return the antecedents
    `double` | `getConsequent()` Gets the internal representation of the class label to be predicted
    `java.lang.String` | `getRevision()` Returns the revision string.
    `void` | `grow(Instances data)` Build one rule using the growing data
    `boolean` | `hasAntds()` Whether this rule has antecedents, i.e.
    `void` | `prune(Instances pruneData, boolean useWhole)` Prune all the possible final sequences of the rule using the pruning data.
    `void` | `setConsequent(double cl)` Sets the internal representation of the class label to be predicted
    `double` | `size()` the number of antecedents of the rule
    `java.lang.String` | `toString(Attribute classAttr)` Prints this rule

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

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

- - ### Constructor Detail

    - #### RipperRule

          public RipperRule()

      Constructor

  - ### Method Detail

    - #### setConsequent

          public void setConsequent(double cl)

      Sets the internal representation of the class label to be predicted
      Parameters:
        `cl` - the internal representation of the class label to be predicted

    - #### getConsequent

          public double getConsequent()

      Gets the internal representation of the class label to be predicted
      Specified by:
        `getConsequent` in class `Rule`
      Returns:
        the internal representation of the class label to be predicted

    - #### copy

          public java.lang.Object copy()

      Get a shallow copy of this rule
      Specified by:
        `copy` in interface `Copyable`
      Overrides:
        `copy` in class `Rule`
      Returns:
        the copy

    - #### covers

          public boolean covers(Instance datum)

      Whether the instance covered by this rule
      Specified by:
        `covers` in class `Rule`
      Parameters:
        `datum` - the instance in question
      Returns:
        the boolean value indicating whether the instance is covered by this rule

    - #### hasAntds

          public boolean hasAntds()

      Whether this rule has antecedents, i.e. whether it is a default rule
      Specified by:
        `hasAntds` in class `Rule`
      Returns:
        the boolean value indicating whether the rule has antecedents

    - #### getAntds

          public java.util.ArrayList<JRip.Antd> getAntds()

      Return the antecedents
      Returns:
        the vector of antecedents

    - #### size

          public double size()

      the number of antecedents of the rule
      Specified by:
        `size` in class `Rule`
      Returns:
        the size of this rule

    - #### grow

          public void grow(Instances data)
                    throws java.lang.Exception

      Build one rule using the growing data
      Specified by:
        `grow` in class `Rule`
      Parameters:
        `data` - the growing data used to build the rule
      Throws:
        `java.lang.Exception` - if the consequent is not set yet

    - #### prune

          public void prune(Instances pruneData,
                            boolean useWhole)

      Prune all the possible final sequences of the rule using the pruning data. The measure used to prune the rule is based on flag given.
      Parameters:
        `pruneData` - the pruning data used to prune the rule
        `useWhole` - flag to indicate whether use the error rate of the whole pruning data instead of the data covered

    - #### toString

          public java.lang.String toString(Attribute classAttr)

      Prints this rule
      Parameters:
        `classAttr` - the class attribute in the data
      Returns:
        a textual description of this rule

    - #### getRevision

          public java.lang.String getRevision()

      Returns the revision string.
      Returns:
        the revision