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<CODE>&nbsp;double</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../weka/core/Instances.html#variance(weka.core.Attribute)">variance</A></B>(<A HREF="../../weka/core/Attribute.html" title="class in weka.core">Attribute</A>&nbsp;att)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Computes the variance for a numeric attribute.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;double</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../weka/core/Instances.html#variance(int)">variance</A></B>(int&nbsp;attIndex)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Computes the variance for a numeric attribute.</TD>
</TR>
</TABLE>
&nbsp;<A NAME="methods_inherited_from_class_java.lang.Object"><!-- --></A>
<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
<TR BGCOLOR="#EEEEFF" CLASS="TableSubHeadingColor">
<TD><B>Methods inherited from class java.lang.Object</B></TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD><CODE>equals, getClass, hashCode, notify, notifyAll, wait, wait, wait</CODE></TD>
</TR>
</TABLE>
&nbsp;
<P>

<!-- ============ FIELD DETAIL =========== -->

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<B>Field Detail</B></FONT></TD>
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</TABLE>

<A NAME="FILE_EXTENSION"><!-- --></A><H3>
FILE_EXTENSION</H3>
<PRE>
public static java.lang.String <B>FILE_EXTENSION</B></PRE>
<DL>
<DD>The filename extension that should be used for arff files
<P>
<DL>
</DL>
</DL>
<HR>

<A NAME="SERIALIZED_OBJ_FILE_EXTENSION"><!-- --></A><H3>
SERIALIZED_OBJ_FILE_EXTENSION</H3>
<PRE>
public static java.lang.String <B>SERIALIZED_OBJ_FILE_EXTENSION</B></PRE>
<DL>
<DD>The filename extension that should be used for bin. serialized instances files
<P>
<DL>
</DL>
</DL>

<!-- ========= CONSTRUCTOR DETAIL ======== -->

<A NAME="constructor_detail"><!-- --></A>
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<B>Constructor Detail</B></FONT></TD>
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<A NAME="Instances(java.io.Reader)"><!-- --></A><H3>
Instances</H3>
<PRE>
public <B>Instances</B>(java.io.Reader&nbsp;reader)
          throws java.io.IOException</PRE>
<DL>
<DD>Reads an ARFF file from a reader, and assigns a weight of
 one to each instance. Lets the index of the class 
 attribute be undefined (negative).
<P>
<DT><B>Parameters:</B><DD><CODE>reader</CODE> - the reader
<DT><B>Throws:</B>
<DD><CODE>java.io.IOException</CODE> - if the ARFF file is not read 
 successfully</DL>
<HR>

<A NAME="Instances(java.io.Reader, int)"><!-- --></A><H3>
Instances</H3>
<PRE>
public <B>Instances</B>(java.io.Reader&nbsp;reader,
                 int&nbsp;capacity)
          throws java.io.IOException</PRE>
<DL>
<DD>Reads the header of an ARFF file from a reader and 
 reserves space for the given number of instances. Lets
 the class index be undefined (negative).
<P>
<DT><B>Parameters:</B><DD><CODE>reader</CODE> - the reader<DD><CODE>capacity</CODE> - the capacity
<DT><B>Throws:</B>
<DD><CODE>java.lang.IllegalArgumentException</CODE> - if the header is not read successfully
 or the capacity is negative.
<DD><CODE>java.io.IOException</CODE> - if there is a problem with the reader.</DL>
<HR>

<A NAME="Instances(weka.core.Instances)"><!-- --></A><H3>
Instances</H3>
<PRE>
public <B>Instances</B>(<A HREF="../../weka/core/Instances.html" title="class in weka.core">Instances</A>&nbsp;dataset)</PRE>
<DL>
<DD>Constructor copying all instances and references to
 the header information from the given set of instances.
<P>
</DL>
<HR>

<A NAME="Instances(weka.core.Instances, int)"><!-- --></A><H3>
Instances</H3>
<PRE>
public <B>Instances</B>(<A HREF="../../weka/core/Instances.html" title="class in weka.core">Instances</A>&nbsp;dataset,
                 int&nbsp;capacity)</PRE>
<DL>
<DD>Constructor creating an empty set of instances. Copies references
 to the header information from the given set of instances. Sets
 the capacity of the set of instances to 0 if its negative.
<P>
<DT><B>Parameters:</B><DD><CODE>capacity</CODE> - the capacity of the new dataset</DL>
<HR>

<A NAME="Instances(weka.core.Instances, int, int)"><!-- --></A><H3>
Instances</H3>
<PRE>
public <B>Instances</B>(<A HREF="../../weka/core/Instances.html" title="class in weka.core">Instances</A>&nbsp;source,
                 int&nbsp;first,
                 int&nbsp;toCopy)</PRE>
<DL>
<DD>Creates a new set of instances by copying a 
 subset of another set.
<P>
<DT><B>Parameters:</B><DD><CODE>source</CODE> - the set of instances from which a subset 
 is to be created<DD><CODE>first</CODE> - the index of the first instance to be copied<DD><CODE>toCopy</CODE> - the number of instances to be copied
<DT><B>Throws:</B>
<DD><CODE>java.lang.IllegalArgumentException</CODE> - if first and toCopy are out of range</DL>
<HR>

<A NAME="Instances(java.lang.String, weka.core.FastVector, int)"><!-- --></A><H3>
Instances</H3>
<PRE>
public <B>Instances</B>(java.lang.String&nbsp;name,
                 <A HREF="../../weka/core/FastVector.html" title="class in weka.core">FastVector</A>&nbsp;attInfo,
                 int&nbsp;capacity)</PRE>
<DL>
<DD>Creates an empty set of instances. Uses the given
 attribute information. Sets the capacity of the set of 
 instances to 0 if its negative. Given attribute information
 must not be changed after this constructor has been used.
<P>
<DT><B>Parameters:</B><DD><CODE>name</CODE> - the name of the relation<DD><CODE>attInfo</CODE> - the attribute information<DD><CODE>capacity</CODE> - the capacity of the set</DL>

<!-- ============ METHOD DETAIL ========== -->

<A NAME="method_detail"><!-- --></A>
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<B>Method Detail</B></FONT></TD>
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<A NAME="stringFreeStructure()"><!-- --></A><H3>
stringFreeStructure</H3>
<PRE>
public <A HREF="../../weka/core/Instances.html" title="class in weka.core">Instances</A> <B>stringFreeStructure</B>()</PRE>
<DL>
<DD>Create a copy of the structure, but "cleanse" string types (i.e.
 doesn't contain references to the strings seen in the past).
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>

<DT><B>Returns:</B><DD>a copy of the instance structure.</DL>
</DD>
</DL>
<HR>

<A NAME="add(weka.core.Instance)"><!-- --></A><H3>
add</H3>
<PRE>
public void <B>add</B>(<A HREF="../../weka/core/Instance.html" title="class in weka.core">Instance</A>&nbsp;instance)</PRE>
<DL>
<DD>Adds one instance to the end of the set. 
 Shallow copies instance before it is added. Increases the
 size of the dataset if it is not large enough. Does not
 check if the instance is compatible with the dataset.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>instance</CODE> - the instance to be added</DL>
</DD>
</DL>
<HR>

<A NAME="attribute(int)"><!-- --></A><H3>
attribute</H3>
<PRE>
public <A HREF="../../weka/core/Attribute.html" title="class in weka.core">Attribute</A> <B>attribute</B>(int&nbsp;index)</PRE>
<DL>
<DD>Returns an attribute.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>index</CODE> - the attribute's index
<DT><B>Returns:</B><DD>the attribute at the given position</DL>
</DD>
</DL>
<HR>

<A NAME="attribute(java.lang.String)"><!-- --></A><H3>
attribute</H3>
<PRE>
public <A HREF="../../weka/core/Attribute.html" title="class in weka.core">Attribute</A> <B>attribute</B>(java.lang.String&nbsp;name)</PRE>
<DL>
<DD>Returns an attribute given its name. If there is more than
 one attribute with the same name, it returns the first one.
 Returns null if the attribute can't be found.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>name</CODE> - the attribute's name
<DT><B>Returns:</B><DD>the attribute with the given name, null if the
 attribute can't be found</DL>
</DD>
</DL>
<HR>

<A NAME="checkForStringAttributes()"><!-- --></A><H3>
checkForStringAttributes</H3>
<PRE>
public boolean <B>checkForStringAttributes</B>()</PRE>
<DL>
<DD>Checks for string attributes in the dataset
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>

<DT><B>Returns:</B><DD>true if string attributes are present, false otherwise</DL>
</DD>
</DL>
<HR>

<A NAME="checkInstance(weka.core.Instance)"><!-- --></A><H3>
checkInstance</H3>
<PRE>
public boolean <B>checkInstance</B>(<A HREF="../../weka/core/Instance.html" title="class in weka.core">Instance</A>&nbsp;instance)</PRE>
<DL>
<DD>Checks if the given instance is compatible
 with this dataset. Only looks at the size of
 the instance and the ranges of the values for 
 nominal and string attributes.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>

<DT><B>Returns:</B><DD>true if the instance is compatible with the dataset</DL>
</DD>
</DL>
<HR>

<A NAME="classAttribute()"><!-- --></A><H3>
classAttribute</H3>
<PRE>
public <A HREF="../../weka/core/Attribute.html" title="class in weka.core">Attribute</A> <B>classAttribute</B>()</PRE>
<DL>
<DD>Returns the class attribute.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>

<DT><B>Returns:</B><DD>the class attribute
<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="classIndex()"><!-- --></A><H3>
classIndex</H3>
<PRE>
public int <B>classIndex</B>()</PRE>
<DL>
<DD>Returns the class attribute's index. Returns negative number
 if it's undefined.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>

<DT><B>Returns:</B><DD>the class index as an integer</DL>
</DD>
</DL>
<HR>

<A NAME="compactify()"><!-- --></A><H3>
compactify</H3>
<PRE>
public void <B>compactify</B>()</PRE>
<DL>
<DD>Compactifies the set of instances. Decreases the capacity of
 the set so that it matches the number of instances in the set.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
</DL>
</DD>
</DL>
<HR>

<A NAME="delete()"><!-- --></A><H3>
delete</H3>
<PRE>
public void <B>delete</B>()</PRE>
<DL>
<DD>Removes all instances from the set.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
</DL>
</DD>
</DL>
<HR>

<A NAME="delete(int)"><!-- --></A><H3>
delete</H3>
<PRE>
public void <B>delete</B>(int&nbsp;index)</PRE>
<DL>
<DD>Removes an instance at the given position from the set.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>index</CODE> - the instance's position</DL>
</DD>
</DL>
<HR>

<A NAME="deleteAttributeAt(int)"><!-- --></A><H3>
deleteAttributeAt</H3>