instances.html

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<PRE>
public void <B>randomize</B>(java.util.Random&nbsp;random)</PRE>
<DL>
<DD>Shuffles the instances in the set so that they are ordered 
 randomly.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>random</CODE> - a random number generator</DL>
</DD>
</DL>
<HR>

<A NAME="readInstance(java.io.Reader)"><!-- --></A><H3>
readInstance</H3>
<PRE>
public boolean <B>readInstance</B>(java.io.Reader&nbsp;reader)
                     throws java.io.IOException</PRE>
<DL>
<DD>Reads a single instance from the reader and appends it
 to the dataset.  Automatically expands the dataset if it
 is not large enough to hold the instance. This method does
 not check for carriage return at the end of the line.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>reader</CODE> - the reader
<DT><B>Returns:</B><DD>false if end of file has been reached
<DT><B>Throws:</B>
<DD><CODE>java.io.IOException</CODE> - if the information is not read 
 successfully</DL>
</DD>
</DL>
<HR>

<A NAME="relationName()"><!-- --></A><H3>
relationName</H3>
<PRE>
public java.lang.String <B>relationName</B>()</PRE>
<DL>
<DD>Returns the relation's name.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>

<DT><B>Returns:</B><DD>the relation's name as a string</DL>
</DD>
</DL>
<HR>

<A NAME="renameAttribute(int, java.lang.String)"><!-- --></A><H3>
renameAttribute</H3>
<PRE>
public void <B>renameAttribute</B>(int&nbsp;att,
                            java.lang.String&nbsp;name)</PRE>
<DL>
<DD>Renames an attribute. This change only affects this
 dataset.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>att</CODE> - the attribute's index<DD><CODE>name</CODE> - the new name</DL>
</DD>
</DL>
<HR>

<A NAME="renameAttribute(weka.core.Attribute, java.lang.String)"><!-- --></A><H3>
renameAttribute</H3>
<PRE>
public void <B>renameAttribute</B>(<A HREF="../../weka/core/Attribute.html" title="class in weka.core">Attribute</A>&nbsp;att,
                            java.lang.String&nbsp;name)</PRE>
<DL>
<DD>Renames an attribute. This change only affects this
 dataset.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>att</CODE> - the attribute<DD><CODE>name</CODE> - the new name</DL>
</DD>
</DL>
<HR>

<A NAME="renameAttributeValue(int, int, java.lang.String)"><!-- --></A><H3>
renameAttributeValue</H3>
<PRE>
public void <B>renameAttributeValue</B>(int&nbsp;att,
                                 int&nbsp;val,
                                 java.lang.String&nbsp;name)</PRE>
<DL>
<DD>Renames the value of a nominal (or string) attribute value. This
 change only affects this dataset.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>att</CODE> - the attribute's index<DD><CODE>val</CODE> - the value's index<DD><CODE>name</CODE> - the new name</DL>
</DD>
</DL>
<HR>

<A NAME="renameAttributeValue(weka.core.Attribute, java.lang.String, java.lang.String)"><!-- --></A><H3>
renameAttributeValue</H3>
<PRE>
public void <B>renameAttributeValue</B>(<A HREF="../../weka/core/Attribute.html" title="class in weka.core">Attribute</A>&nbsp;att,
                                 java.lang.String&nbsp;val,
                                 java.lang.String&nbsp;name)</PRE>
<DL>
<DD>Renames the value of a nominal (or string) attribute value. This
 change only affects this dataset.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>att</CODE> - the attribute<DD><CODE>val</CODE> - the value<DD><CODE>name</CODE> - the new name</DL>
</DD>
</DL>
<HR>

<A NAME="resample(java.util.Random)"><!-- --></A><H3>
resample</H3>
<PRE>
public <A HREF="../../weka/core/Instances.html" title="class in weka.core">Instances</A> <B>resample</B>(java.util.Random&nbsp;random)</PRE>
<DL>
<DD>Creates a new dataset of the same size using random sampling
 with replacement.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>random</CODE> - a random number generator
<DT><B>Returns:</B><DD>the new dataset</DL>
</DD>
</DL>
<HR>

<A NAME="resampleWithWeights(java.util.Random)"><!-- --></A><H3>
resampleWithWeights</H3>
<PRE>
public <A HREF="../../weka/core/Instances.html" title="class in weka.core">Instances</A> <B>resampleWithWeights</B>(java.util.Random&nbsp;random)</PRE>
<DL>
<DD>Creates a new dataset of the same size using random sampling
 with replacement according to the current instance weights. The
 weights of the instances in the new dataset are set to one.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>random</CODE> - a random number generator
<DT><B>Returns:</B><DD>the new dataset</DL>
</DD>
</DL>
<HR>

<A NAME="resampleWithWeights(java.util.Random, double[])"><!-- --></A><H3>
resampleWithWeights</H3>
<PRE>
public <A HREF="../../weka/core/Instances.html" title="class in weka.core">Instances</A> <B>resampleWithWeights</B>(java.util.Random&nbsp;random,
                                     double[]&nbsp;weights)</PRE>
<DL>
<DD>Creates a new dataset of the same size using random sampling
 with replacement according to the given weight vector. The
 weights of the instances in the new dataset are set to one.
 The length of the weight vector has to be the same as the
 number of instances in the dataset, and all weights have to
 be positive.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>random</CODE> - a random number generator<DD><CODE>weights</CODE> - the weight vector
<DT><B>Returns:</B><DD>the new dataset
<DT><B>Throws:</B>
<DD><CODE>java.lang.IllegalArgumentException</CODE> - if the weights array is of the wrong
 length or contains negative weights.</DL>
</DD>
</DL>
<HR>

<A NAME="setClass(weka.core.Attribute)"><!-- --></A><H3>
setClass</H3>
<PRE>
public void <B>setClass</B>(<A HREF="../../weka/core/Attribute.html" title="class in weka.core">Attribute</A>&nbsp;att)</PRE>
<DL>
<DD>Sets the class attribute.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>att</CODE> - attribute to be the class</DL>
</DD>
</DL>
<HR>

<A NAME="setClassIndex(int)"><!-- --></A><H3>
setClassIndex</H3>
<PRE>
public void <B>setClassIndex</B>(int&nbsp;classIndex)</PRE>
<DL>
<DD>Sets the class index of the set.
 If the class index is negative there is assumed to be no class.
 (ie. it is undefined)
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>classIndex</CODE> - the new class index
<DT><B>Throws:</B>
<DD><CODE>java.lang.IllegalArgumentException</CODE> - if the class index is too big or < 0</DL>
</DD>
</DL>
<HR>

<A NAME="setRelationName(java.lang.String)"><!-- --></A><H3>
setRelationName</H3>
<PRE>
public void <B>setRelationName</B>(java.lang.String&nbsp;newName)</PRE>
<DL>
<DD>Sets the relation's name.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>newName</CODE> - the new relation name.</DL>
</DD>
</DL>
<HR>

<A NAME="sort(int)"><!-- --></A><H3>
sort</H3>
<PRE>
public void <B>sort</B>(int&nbsp;attIndex)</PRE>
<DL>
<DD>Sorts the instances based on an attribute. For numeric attributes, 
 instances are sorted in ascending order. For nominal attributes, 
 instances are sorted based on the attribute label ordering 
 specified in the header. Instances with missing values for the 
 attribute are placed at the end of the dataset.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>attIndex</CODE> - the attribute's index</DL>
</DD>
</DL>
<HR>

<A NAME="sort(weka.core.Attribute)"><!-- --></A><H3>
sort</H3>
<PRE>
public void <B>sort</B>(<A HREF="../../weka/core/Attribute.html" title="class in weka.core">Attribute</A>&nbsp;att)</PRE>
<DL>
<DD>Sorts the instances based on an attribute. For numeric attributes, 
 instances are sorted into ascending order. For nominal attributes, 
 instances are sorted based on the attribute label ordering 
 specified in the header. Instances with missing values for the 
 attribute are placed at the end of the dataset.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>att</CODE> - the attribute</DL>
</DD>
</DL>
<HR>

<A NAME="stratify(int)"><!-- --></A><H3>
stratify</H3>
<PRE>
public void <B>stratify</B>(int&nbsp;numFolds)</PRE>
<DL>
<DD>Stratifies a set of instances according to its class values 
 if the class attribute is nominal (so that afterwards a 
 stratified cross-validation can be performed).
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>numFolds</CODE> - the number of folds in the cross-validation
<DT><B>Throws:</B>
<DD><CODE><A HREF="../../weka/core/UnassignedClassException.html" title="class in weka.core">UnassignedClassException</A></CODE> - if the class is not set</DL>
</DD>
</DL>
<HR>

<A NAME="sumOfWeights()"><!-- --></A><H3>
sumOfWeights</H3>
<PRE>
public double <B>sumOfWeights</B>()</PRE>
<DL>
<DD>Computes the sum of all the instances' weights.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>

<DT><B>Returns:</B><DD>the sum of all the instances' weights as a double</DL>
</DD>
</DL>
<HR>

<A NAME="testCV(int, int)"><!-- --></A><H3>
testCV</H3>
<PRE>
public <A HREF="../../weka/core/Instances.html" title="class in weka.core">Instances</A> <B>testCV</B>(int&nbsp;numFolds,
                        int&nbsp;numFold)</PRE>
<DL>
<DD>Creates the test set for one fold of a cross-validation on 
 the dataset.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>numFolds</CODE> - the number of folds in the cross-validation. Must
 be greater than 1.<DD><CODE>numFold</CODE> - 0 for the first fold, 1 for the second, ...
<DT><B>Returns:</B><DD>the test set as a set of weighted instances
<DT><B>Throws:</B>
<DD><CODE>java.lang.IllegalArgumentException</CODE> - if the number of folds is less than 2
 or greater than the number of instances.</DL>
</DD>
</DL>
<HR>

<A NAME="toString()"><!-- --></A><H3>
toString</H3>
<PRE>
public java.lang.String <B>toString</B>()</PRE>
<DL>
<DD>Returns the dataset as a string in ARFF format. Strings
 are quoted if they contain whitespace characters, or if they
 are a question mark.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>

<DT><B>Returns:</B><DD>the dataset in ARFF format as a string</DL>
</DD>
</DL>
<HR>

<A NAME="trainCV(int, int)"><!-- --></A><H3>
trainCV</H3>
<PRE>
public <A HREF="../../weka/core/I