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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><!--NewPage--><HTML><HEAD><!-- Generated by javadoc (build 1.4.2_05) on Mon Mar 07 15:27:46 NZDT 2005 --><TITLE>Instances</TITLE><META NAME="keywords" CONTENT="weka.core.Instances class"><LINK REL ="stylesheet" TYPE="text/css" HREF="../../stylesheet.css" TITLE="Style"><SCRIPT type="text/javascript">function windowTitle(){ parent.document.title="Instances";}</SCRIPT></HEAD><BODY BGCOLOR="white" onload="windowTitle();"><!-- ========= START OF TOP NAVBAR ======= --><A NAME="navbar_top"><!-- --></A><A HREF="#skip-navbar_top" title="Skip navigation links"></A><TABLE BORDER="0" WIDTH="100%" CELLPADDING="1" CELLSPACING="0" SUMMARY=""><TR><TD COLSPAN=3 BGCOLOR="#EEEEFF" CLASS="NavBarCell1"><A NAME="navbar_top_firstrow"><!-- --></A><TABLE BORDER="0" CELLPADDING="0" CELLSPACING="3" SUMMARY=""> <TR ALIGN="center" VALIGN="top"> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../overview-summary.html"><FONT CLASS="NavBarFont1"><B>Overview</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-summary.html"><FONT CLASS="NavBarFont1"><B>Package</B></FONT></A> </TD> <TD BGCOLOR="#FFFFFF" CLASS="NavBarCell1Rev"> <FONT CLASS="NavBarFont1Rev"><B>Class</B></FONT> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-tree.html"><FONT CLASS="NavBarFont1"><B>Tree</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../deprecated-list.html"><FONT CLASS="NavBarFont1"><B>Deprecated</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../index-all.html"><FONT CLASS="NavBarFont1"><B>Index</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../Tutorial.pdf"><FONT CLASS="NavBarFont1"><B>Help</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="http://www.cs.waikato.ac.nz/ml/weka/index.html"><FONT CLASS="NavBarFont1"><B>Weka's home</B></FONT></A> </TD> </TR></TABLE></TD><TD ALIGN="right" VALIGN="top" ROWSPAN=3><EM></EM></TD></TR><TR><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../weka/core/Instance.html" title="class in weka.core"><B>PREV CLASS</B></A> <A HREF="../../weka/core/Matrix.html" title="class in weka.core"><B>NEXT CLASS</B></A></FONT></TD><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../index.html" target="_top"><B>FRAMES</B></A> <A HREF="Instances.html" target="_top"><B>NO FRAMES</B></A> <SCRIPT type="text/javascript"> <!-- if(window==top) { document.writeln('<A HREF="../../allclasses-noframe.html"><B>All Classes</B></A>'); } //--></SCRIPT><NOSCRIPT> <A HREF="../../allclasses-noframe.html"><B>All Classes</B></A></NOSCRIPT></FONT></TD></TR><TR><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2"> SUMMARY: NESTED | <A HREF="#field_summary">FIELD</A> | <A HREF="#constructor_summary">CONSTR</A> | <A HREF="#method_summary">METHOD</A></FONT></TD><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2">DETAIL: <A HREF="#field_detail">FIELD</A> | <A HREF="#constructor_detail">CONSTR</A> | <A HREF="#method_detail">METHOD</A></FONT></TD></TR></TABLE><A NAME="skip-navbar_top"></A><!-- ========= END OF TOP NAVBAR ========= --><HR><!-- ======== START OF CLASS DATA ======== --><H2><FONT SIZE="-1">weka.core</FONT><BR>Class Instances</H2><PRE>java.lang.Object <IMG SRC="../../resources/inherit.gif" ALT="extended by"><B>weka.core.Instances</B></PRE><DL><DT><B>All Implemented Interfaces:</B> <DD>java.io.Serializable</DD></DL><DL><DT><B>Direct Known Subclasses:</B> <DD><A HREF="../../weka/associations/tertius/IndividualInstances.html" title="class in weka.associations.tertius">IndividualInstances</A>, <A HREF="../../weka/classifiers/trees/adtree/ReferenceInstances.html" title="class in weka.classifiers.trees.adtree">ReferenceInstances</A></DD></DL><HR><DL><DT>public class <B>Instances</B><DT>extends java.lang.Object<DT>implements java.io.Serializable</DL><P>Class for handling an ordered set of weighted instances. <p> Typical usage (code from the main() method of this class): <p> <code> ... <br> // Read all the instances in the file <br> reader = new FileReader(filename); <br> instances = new Instances(reader); <br><br> // Make the last attribute be the class <br> instances.setClassIndex(instances.numAttributes() - 1); <br><br> // Print header and instances. <br> System.out.println("\nDataset:\n"); <br> System.out.println(instances); <br><br> ... <br> </code><p> All methods that change a set of instances are safe, ie. a change of a set of instances does not affect any other sets of instances. All methods that change a datasets's attribute information clone the dataset before it is changed.<P><P><DL><DT><B>Version:</B></DT> <DD>$Revision: 1.58.2.1 $</DD><DT><B>Author:</B></DT> <DD>Eibe Frank (eibe@cs.waikato.ac.nz), Len Trigg (trigg@cs.waikato.ac.nz)</DD><DT><B>See Also:</B><DD><A HREF="../../serialized-form.html#weka.core.Instances">Serialized Form</A></DL><HR><P><!-- ======== NESTED CLASS SUMMARY ======== --><!-- =========== FIELD SUMMARY =========== --><A NAME="field_summary"><!-- --></A><TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TD COLSPAN=2><FONT SIZE="+2"><B>Field Summary</B></FONT></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static java.lang.String</CODE></FONT></TD><TD><CODE><B><A HREF="../../weka/core/Instances.html#FILE_EXTENSION">FILE_EXTENSION</A></B></CODE><BR> The filename extension that should be used for arff files</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static java.lang.String</CODE></FONT></TD><TD><CODE><B><A HREF="../../weka/core/Instances.html#SERIALIZED_OBJ_FILE_EXTENSION">SERIALIZED_OBJ_FILE_EXTENSION</A></B></CODE><BR> The filename extension that should be used for bin.</TD></TR></TABLE> <!-- ======== CONSTRUCTOR SUMMARY ======== --><A NAME="constructor_summary"><!-- --></A><TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TD COLSPAN=2><FONT SIZE="+2"><B>Constructor Summary</B></FONT></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD><CODE><B><A HREF="../../weka/core/Instances.html#Instances(weka.core.Instances)">Instances</A></B>(<A HREF="../../weka/core/Instances.html" title="class in weka.core">Instances</A> dataset)</CODE><BR> Constructor copying all instances and references to the header information from the given set of instances.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD><CODE><B><A HREF="../../weka/core/Instances.html#Instances(weka.core.Instances, int)">Instances</A></B>(<A HREF="../../weka/core/Instances.html" title="class in weka.core">Instances</A> dataset, int capacity)</CODE><BR> Constructor creating an empty set of instances.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD><CODE><B><A HREF="../../weka/core/Instances.html#Instances(weka.core.Instances, int, int)">Instances</A></B>(<A HREF="../../weka/core/Instances.html" title="class in weka.core">Instances</A> source, int first, int toCopy)</CODE><BR> Creates a new set of instances by copying a subset of another set.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD><CODE><B><A HREF="../../weka/core/Instances.html#Instances(java.io.Reader)">Instances</A></B>(java.io.Reader reader)</CODE><BR> Reads an ARFF file from a reader, and assigns a weight of one to each instance.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD><CODE><B><A HREF="../../weka/core/Instances.html#Instances(java.io.Reader, int)">Instances</A></B>(java.io.Reader reader, int capacity)</CODE><BR> Reads the header of an ARFF file from a reader and reserves space for the given number of instances.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD><CODE><B><A HREF="../../weka/core/Instances.html#Instances(java.lang.String, weka.core.FastVector, int)">Instances</A></B>(java.lang.String name, <A HREF="../../weka/core/FastVector.html" title="class in weka.core">FastVector</A> attInfo, int capacity)</CODE><BR> Creates an empty set of instances.</TD></TR></TABLE> <!-- ========== METHOD SUMMARY =========== --><A NAME="method_summary"><!-- --></A><TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TD COLSPAN=2><FONT SIZE="+2"><B>Method Summary</B></FONT></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> void</CODE></FONT></TD><TD><CODE><B><A HREF="../../weka/core/Instances.html#add(weka.core.Instance)">add</A></B>(<A HREF="../../weka/core/Instance.html" title="class in weka.core">Instance</A> instance)</CODE><BR> Adds one instance to the end of the set.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> <A HREF="../../weka/core/Attribute.html" title="class in weka.core">Attribute</A></CODE></FONT></TD><TD><CODE><B><A HREF="../../weka/core/Instances.html#attribute(int)">attribute</A></B>(int index)</CODE><BR> Returns an attribute.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> <A HREF="../../weka/core/Attribute.html" title="class in weka.core">Attribute</A></CODE></FONT></TD><TD><CODE><B><A HREF="../../weka/core/Instances.html#attribute(java.lang.String)">attribute</A></B>(java.lang.String name)</CODE><BR> Returns an attribute given its name.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> <A HREF="../../weka/core/AttributeStats.html" title="class in weka.core">AttributeStats</A></CODE></FONT></TD><TD><CODE><B><A HREF="../../weka/core/Instances.html#attributeStats(int)">attributeStats</A></B>(int index)</CODE><BR> Calculates summary statistics on the values that appear in this set of instances for a specified attribute.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> double[]</CODE></FONT></TD><TD><CODE><B><A HREF="../../weka/core/Instances.html#attributeToDoubleArray(int)">attributeToDoubleArray</A></B>(int index)</CODE><BR> Gets the value of all instances in this dataset for a particular attribute.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> boolean</CODE></FONT></TD><TD><CODE><B><A HREF="../../weka/core/Instances.html#checkForStringAttributes()">checkForStringAttributes</A></B>()</CODE><BR> Checks for string attributes in the dataset</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> boolean</CODE></FONT></TD><TD><CODE><B><A HREF="../../weka/core/Instances.html#checkInstance(weka.core.Instance)">checkInstance</A></B>(<A HREF="../../weka/core/Instance.html" title="class in weka.core">Instance</A> instance)</CODE><BR> Checks if the given instance is compatible with this dataset.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> <A HREF="../../weka/core/Attribute.html" title="class in weka.core">Attribute</A></CODE></FONT></TD><TD><CODE><B><A HREF="../../weka/core/Instances.html#classAttribute()">classAttribute</A></B>()</CODE><BR> Returns the class attribute.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> int</CODE></FONT></TD><TD><CODE><B><A HREF="../../weka/core/Instances.html#classIndex()">classIndex</A></B>()</CODE><BR> Returns the class attribute's index.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> void</CODE></FONT></TD><TD><CODE><B><A HREF="../../weka/core/Instances.html#compactify()">compactify</A></B>()</CODE><BR> Compactifies the set of instances.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> void</CODE></FONT></TD><TD><CODE><B><A HREF="../../weka/core/Instances.html#delete()">delete</A></B>()</CODE><BR> Removes all instances from the set.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> void</CODE></FONT></TD><TD><CODE><B><A HREF="../../weka/core/Instances.html#delete(int)">delete</A></B>(int index)</CODE><BR> Removes an instance at the given position from the set.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> void</CODE></FONT></TD><TD><CODE><B><A HREF="../../weka/core/Instances.html#deleteAttributeAt(int)">deleteAttributeAt</A></B>(int position)</CODE><BR> Deletes an attribute at the given position (0 to numAttributes() - 1).</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> void</CODE></FONT></TD><TD><CODE><B><A HREF="../../weka/core/Instances.html#deleteStringAttributes()">deleteStringAttributes</A></B>()</CODE><BR> Deletes all string attributes in the dataset.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> void</CODE></FONT></TD><TD><CODE><B><A HREF="../../weka/core/Instances.html#deleteWithMissing(weka.core.Attribute)">deleteWithMissing</A></B>(<A HREF="../../weka/core/Attribute.html" title="class in weka.core">Attribute</A> att)</CODE><BR> Removes all instances with missing values for a particular attribute from the dataset.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> void</CODE></FONT></TD><TD><CODE><B><A HREF="../../weka/core/Instances.html#deleteWithMissing(int)">deleteWithMissing</A></B>(int attIndex)</CODE><BR> Removes all instances with missing values for a particular attribute from the dataset.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> void</CODE></FONT></TD><TD><CODE><B><A HREF="../../weka/core/Instances.html#deleteWithMissingClass()">deleteWithMissingClass</A></B>()</CODE>⌨️ 快捷键说明
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