instance.html

< 数据挖掘--实用机器学习技术及java实现> 一书结合数据挖掘和机器学习的知识,作者陈述了自动挖掘模式的基础理论,并且以java语言实现了具有代表性的各类数据挖掘方法.例如:class

<DT><B>Returns:</B><DD>the class attribute<DT><B>Throws:</B><DD><CODE><A HREF="../../weka/core/UnassignedDatasetException.html">UnassignedDatasetException</A></CODE> - if the class is not set or the
 instance doesn't have access to a dataset</DL>
</DD>
</DL>
<HR>

<A NAME="classIndex()"><!-- --></A><H3>
classIndex</H3>
<PRE>
public int <B>classIndex</B>()</PRE>
<DL>
<DD>Returns the class attribute's index.<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Returns:</B><DD>the class index as an integer<DT><B>Throws:</B><DD><CODE><A HREF="../../weka/core/UnassignedDatasetException.html">UnassignedDatasetException</A></CODE> - if instance doesn't have access to a dataset</DL>
</DD>
</DL>
<HR>

<A NAME="classIsMissing()"><!-- --></A><H3>
classIsMissing</H3>
<PRE>
public boolean <B>classIsMissing</B>()</PRE>
<DL>
<DD>Tests if an instance's class is missing.<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Returns:</B><DD>true if the instance's class is missing<DT><B>Throws:</B><DD><CODE><A HREF="../../weka/core/UnassignedClassException.html">UnassignedClassException</A></CODE> - if the class is not set or the instance doesn't
 have access to a dataset</DL>
</DD>
</DL>
<HR>

<A NAME="classValue()"><!-- --></A><H3>
classValue</H3>
<PRE>
public double <B>classValue</B>()</PRE>
<DL>
<DD>Returns an instance's class value in internal format. (ie. as a
 floating-point number)<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Returns:</B><DD>the corresponding value as a double (If the 
 corresponding attribute is nominal (or a string) then it returns the 
 value's index as a double).<DT><B>Throws:</B><DD><CODE><A HREF="../../weka/core/UnassignedClassException.html">UnassignedClassException</A></CODE> - if the class is not set or the instance doesn't
 have access to a dataset</DL>
</DD>
</DL>
<HR>

<A NAME="copy()"><!-- --></A><H3>
copy</H3>
<PRE>
public java.lang.Object <B>copy</B>()</PRE>
<DL>
<DD>Produces a shallow copy of this instance. The copy has
 access to the same dataset. (if you want to make a copy
 that doesn't have access to the dataset, use 
 <code>new Instance(instance)</code><DD><DL>
<DT><B>Specified by: </B><DD><CODE><A HREF="../../weka/core/Copyable.html#copy()">copy</A></CODE> in interface <CODE><A HREF="../../weka/core/Copyable.html">Copyable</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Returns:</B><DD>the shallow copy</DL>
</DD>
</DL>
<HR>

<A NAME="dataset()"><!-- --></A><H3>
dataset</H3>
<PRE>
public <A HREF="../../weka/core/Instances.html">Instances</A> <B>dataset</B>()</PRE>
<DL>
<DD>Returns the dataset this instance has access to. (ie. obtains
 information about attribute types from) Null if the instance
 doesn't have access to a dataset.<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Returns:</B><DD>the dataset the instance has accesss to</DL>
</DD>
</DL>
<HR>

<A NAME="deleteAttributeAt(int)"><!-- --></A><H3>
deleteAttributeAt</H3>
<PRE>
public void <B>deleteAttributeAt</B>(int&nbsp;position)</PRE>
<DL>
<DD>Deletes an attribute at the given position (0 to 
 numAttributes() - 1). Only succeeds if the instance does not
 have access to any dataset because otherwise inconsistencies
 could be introduced.<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>pos</CODE> - the attribute's position<DT><B>Throws:</B><DD><CODE>java.lang.RuntimeException</CODE> - if the instance has access to a
 dataset</DL>
</DD>
</DL>
<HR>

<A NAME="enumerateAttributes()"><!-- --></A><H3>
enumerateAttributes</H3>
<PRE>
public java.util.Enumeration <B>enumerateAttributes</B>()</PRE>
<DL>
<DD>Returns an enumeration of all the attributes.<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Returns:</B><DD>enumeration of all the attributes<DT><B>Throws:</B><DD><CODE><A HREF="../../weka/core/UnassignedDatasetException.html">UnassignedDatasetException</A></CODE> - if the instance doesn't
 have access to a dataset</DL>
</DD>
</DL>
<HR>

<A NAME="equalHeaders(weka.core.Instance)"><!-- --></A><H3>
equalHeaders</H3>
<PRE>
public boolean <B>equalHeaders</B>(<A HREF="../../weka/core/Instance.html">Instance</A>&nbsp;inst)</PRE>
<DL>
<DD>Tests if the headers of two instances are equivalent.<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>instance</CODE> - another instance<DT><B>Returns:</B><DD>true if the header of the given instance is 
 equivalent to this instance's header<DT><B>Throws:</B><DD><CODE><A HREF="../../weka/core/UnassignedDatasetException.html">UnassignedDatasetException</A></CODE> - if instance doesn't have access to any
 dataset</DL>
</DD>
</DL>
<HR>

<A NAME="index(int)"><!-- --></A><H3>
index</H3>
<PRE>
public int <B>index</B>(int&nbsp;position)</PRE>
<DL>
<DD>Returns the index of the attribute stored at the given position.
 Just returns the given value.<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>position</CODE> - the position<DT><B>Returns:</B><DD>the index of the attribute stored at the given position</DL>
</DD>
</DL>
<HR>

<A NAME="insertAttributeAt(int)"><!-- --></A><H3>
insertAttributeAt</H3>
<PRE>
public void <B>insertAttributeAt</B>(int&nbsp;position)</PRE>
<DL>
<DD>Inserts an attribute at the given position (0 to 
 numAttributes()). Only succeeds if the instance does not
 have access to any dataset because otherwise inconsistencies
 could be introduced.<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>pos</CODE> - the attribute's position<DT><B>Throws:</B><DD><CODE>java.lang.RuntimeException</CODE> - if the instance has accesss to a
 dataset<DD><CODE>java.lang.IllegalArgumentException</CODE> - if the position is out of range</DL>
</DD>
</DL>
<HR>

<A NAME="isMissing(int)"><!-- --></A><H3>
isMissing</H3>
<PRE>
public boolean <B>isMissing</B>(int&nbsp;attIndex)</PRE>
<DL>
<DD>Tests if a specific value is "missing".<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>attIndex</CODE> - the attribute's index</DL>
</DD>
</DL>
<HR>

<A NAME="isMissingSparse(int)"><!-- --></A><H3>
isMissingSparse</H3>
<PRE>
public boolean <B>isMissingSparse</B>(int&nbsp;indexOfIndex)</PRE>
<DL>
<DD>Tests if a specific value is "missing". Does
 the same thing as isMissing() if applied to an Instance.<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>indexOfIndex</CODE> - the index of the attribute's index</DL>
</DD>
</DL>
<HR>

<A NAME="isMissing(weka.core.Attribute)"><!-- --></A><H3>
isMissing</H3>
<PRE>
public boolean <B>isMissing</B>(<A HREF="../../weka/core/Attribute.html">Attribute</A>&nbsp;att)</PRE>
<DL>
<DD>Tests if a specific value is "missing".
 The given attribute has to belong to a dataset.<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>att</CODE> - the attribute</DL>
</DD>
</DL>
<HR>

<A NAME="isMissingValue(double)"><!-- --></A><H3>
isMissingValue</H3>
<PRE>
public static boolean <B>isMissingValue</B>(double&nbsp;val)</PRE>
<DL>
<DD>Tests if the given value codes "missing".<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>val</CODE> - the value to be tested<DT><B>Returns:</B><DD>true if val codes "missing"</DL>
</DD>
</DL>
<HR>

<A NAME="mergeInstance(weka.core.Instance)"><!-- --></A><H3>
mergeInstance</H3>
<PRE>
public <A HREF="../../weka/core/Instance.html">Instance</A> <B>mergeInstance</B>(<A HREF="../../weka/core/Instance.html">Instance</A>&nbsp;inst)</PRE>
<DL>
<DD>Merges this instance with the given instance and returns
 the result. Dataset is set to null.<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>inst</CODE> - the instance to be merged with this one<DT><B>Returns:</B><DD>the merged instances</DL>
</DD>
</DL>
<HR>

<A NAME="missingValue()"><!-- --></A><H3>
missingValue</H3>
<PRE>
public static double <B>missingValue</B>()</PRE>
<DL>
<DD>Returns the double that codes "missing".<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Returns:</B><DD>the double that codes "missing"</DL>
</DD>
</DL>
<HR>

<A NAME="numAttributes()"><!-- --></A><H3>
numAttributes</H3>
<PRE>
public int <B>numAttributes</B>()</PRE>
<DL>
<DD>Returns the number of attributes.<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Returns:</B><DD>the number of attributes as an integer</DL>
</DD>
</DL>
<HR>

<A NAME="numClasses()"><!-- --></A><H3>
numClasses</H3>
<PRE>
public int <B>numClasses</B>()</PRE>
<DL>
<DD>Returns the number of class labels.<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Returns:</B><DD>the number of class labels as an integer if the 
 class attribute is nominal, 1 otherwise.<DT><B>Throws:</B><DD><CODE><A HREF="../../weka/core/UnassignedDatasetException.html">UnassignedDatasetException</A></CODE> - if instance doesn't have access to any
 dataset</DL>
</DD>
</DL>
<HR>

<A NAME="numValues()"><!-- --></A><H3>
numValues</H3>
<PRE>
public int <B>numValues</B>()</PRE>
<DL>
<DD>Returns the number of values present. Always the same as numAttributes().<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Returns:</B><DD>the number of values</DL>
</DD>
</DL>
<HR>

<A NAME="replaceMissingValues(double[])"><!-- --></A><H3>
replaceMissingValues</H3>
<PRE>
public void <B>replaceMissingValues</B>(double[]&nbsp;array)</PRE>
<DL>
<DD>Replaces all missing values in the instance with the
 values contained in the given array. A deep copy of
 the vector of attribute values is performed before the
 values are replaced.<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>array</CODE> - containing the means and modes<DT><B>Throws:</B><DD><CODE>java.lang.IllegalArgumentException</CODE> - if numbers of attributes are unequal</DL>
</DD>
</DL>
<HR>

<A NAME="setClassMissing()"><!-- --></A><H3>
setClassMissing</H3>
<PRE>
public void <B>setClassMissing</B>()</PRE>
<DL>
<DD>Sets the class value of an instance to be "missing". A deep copy of
 the vector of attribute values is performed before the
 value is set to be missing.<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Throws:</B><DD><CODE><A HREF="../../weka/core/UnassignedClassException.html">UnassignedClassException</A></CODE> - if the class is not set<DD><CODE><A HREF="../../weka/core/UnassignedDatasetException.html">UnassignedDatasetException</A></CODE> - if the instance doesn't
 have access to a dataset</DL>
</DD>
</DL>
<HR>

<A NAME="setClassValue(double)"><!-- --></A><H3>
setClassValue</H3>
<PRE>
public void <B>setClassValue</B>(double&nbsp;value)</PRE>
<DL>
<DD>Sets the class value of an instance to the given value (internal
 floating-point format).  A deep copy of the vector of attribute
 values is performed before the value is set.<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>value</CODE> - the new attribute value (If the corresponding
 attribute is nominal (or a string) then this is the new value's
 index as a double).<DT><B>Throws:</B><DD><CODE><A HREF="../../weka/core/UnassignedClassException.html">UnassignedClassException</A></CODE> - if the class is not set<DD><CODE>UnaddignedDatasetException</CODE> - if the instance doesn't
 have access to a dataset</DL>
</DD>
</DL>
<HR>

<A NAME="setClassValue(java.lang.String)"><!-- --></A><H3>
setClassValue</H3>
<PRE>
public final void <B>setClassValue</B>(java.lang.String&nbsp;value)</PRE>
<DL>
<DD>Sets the class value of an instance to the given value. A deep
 copy of the vector of attribute values is performed before the
 value is set.<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>value</CODE> - the new class value (If the class
 is a string attribute and the value can't be found,
 the value is added to the attribute).<DT><B>Throws:</B><DD><CODE><A HREF="../../weka/core/UnassignedClassException.html">UnassignedClassException</A></CODE> - if the class is not set<DD><CODE><A HREF="../../weka/core/UnassignedDatasetException.html">UnassignedDatasetException</A></CODE> - if the dataset is not set<DD><CODE>java.lang.IllegalArgumentException</CODE> - if the attribute is not
 nominal or a string, or the value couldn't be found for a nominal
 attribute</DL>
</DD>
</DL>
<HR>

<A NAME="setDataset(weka.core.Instances)"><!-- --></A><H3>
setDataset</H3>
<PRE>
public final void <B>setDataset</B>(<A HREF="../../weka/core/Instances.html">Instances</A>&nbsp;instances)</PRE>
<DL>
<DD>Sets the reference to the dataset. Does not check if the instance
 is compatible with the dataset. Note: the dataset does not know
 about this instance. If the structure of the dataset's header
 gets changed, this instance will not be adjusted automatically.<DD><DL>
</DL>
</DD>