utils.html

数据挖掘的最常用工具。由于开源

<DD><DL>
<DT><B>Parameters:</B><DD><CODE>flag</CODE> - the character indicating the option.<DD><CODE>options</CODE> - the array of strings containing all the options.
<DT><B>Returns:</B><DD>the indicated option or an empty string
<DT><B>Throws:</B>
<DD><CODE>java.lang.Exception</CODE> - if the option indicated by the flag can't be found</DL>
</DD>
</DL>
<HR>

<A NAME="getOption(java.lang.String, java.lang.String[])"><!-- --></A><H3>
getOption</H3>
<PRE>
public static java.lang.String <B>getOption</B>(java.lang.String&nbsp;flag,
                                         java.lang.String[]&nbsp;options)
                                  throws java.lang.Exception</PRE>
<DL>
<DD>Gets an option indicated by a flag "-String" from the given array
 of strings. Stops searching at the first marker "--". Replaces 
 flag and option with empty strings.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>flag</CODE> - the String indicating the option.<DD><CODE>options</CODE> - the array of strings containing all the options.
<DT><B>Returns:</B><DD>the indicated option or an empty string
<DT><B>Throws:</B>
<DD><CODE>java.lang.Exception</CODE> - if the option indicated by the flag can't be found</DL>
</DD>
</DL>
<HR>

<A NAME="getOptionPos(char, java.lang.String[])"><!-- --></A><H3>
getOptionPos</H3>
<PRE>
public static int <B>getOptionPos</B>(char&nbsp;flag,
                               java.lang.String[]&nbsp;options)</PRE>
<DL>
<DD>Gets the index of an option or flag indicated by a flag "-Char" from 
 the given array of strings. Stops searching at the first marker "--".
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>flag</CODE> - the character indicating the option.<DD><CODE>options</CODE> - the array of strings containing all the options.
<DT><B>Returns:</B><DD>the position if found, or -1 otherwise</DL>
</DD>
</DL>
<HR>

<A NAME="getOptionPos(java.lang.String, java.lang.String[])"><!-- --></A><H3>
getOptionPos</H3>
<PRE>
public static int <B>getOptionPos</B>(java.lang.String&nbsp;flag,
                               java.lang.String[]&nbsp;options)</PRE>
<DL>
<DD>Gets the index of an option or flag indicated by a flag "-String" from 
 the given array of strings. Stops searching at the first marker "--".
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>flag</CODE> - the String indicating the option.<DD><CODE>options</CODE> - the array of strings containing all the options.
<DT><B>Returns:</B><DD>the position if found, or -1 otherwise</DL>
</DD>
</DL>
<HR>

<A NAME="quote(java.lang.String)"><!-- --></A><H3>
quote</H3>
<PRE>
public static java.lang.String <B>quote</B>(java.lang.String&nbsp;string)</PRE>
<DL>
<DD>Quotes a string if it contains special characters.
 
 The following rules are applied:

 A character is backquoted version of it is one 
 of <tt>" ' % \ \n \r \t</tt>.

 A string is enclosed within single quotes if a character has been
 backquoted using the previous rule above or contains 
 <tt>{ }</tt> or is exactly equal to the strings 
 <tt>, ? space or ""</tt> (empty string).

 A quoted question mark distinguishes it from the missing value which
 is represented as an unquoted question mark in arff files.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>string</CODE> - the string to be quoted
<DT><B>Returns:</B><DD>the string (possibly quoted)<DT><B>See Also:</B><DD><A HREF="../../weka/core/Utils.html#unquote(java.lang.String)"><CODE>unquote(String)</CODE></A></DL>
</DD>
</DL>
<HR>

<A NAME="unquote(java.lang.String)"><!-- --></A><H3>
unquote</H3>
<PRE>
public static java.lang.String <B>unquote</B>(java.lang.String&nbsp;string)</PRE>
<DL>
<DD>unquotes are previously quoted string (but only if necessary), i.e., it
 removes the single quotes around it. Inverse to quote(String).
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>string</CODE> - the string to process
<DT><B>Returns:</B><DD>the unquoted string<DT><B>See Also:</B><DD><A HREF="../../weka/core/Utils.html#quote(java.lang.String)"><CODE>quote(String)</CODE></A></DL>
</DD>
</DL>
<HR>

<A NAME="backQuoteChars(java.lang.String)"><!-- --></A><H3>
backQuoteChars</H3>
<PRE>
public static java.lang.String <B>backQuoteChars</B>(java.lang.String&nbsp;string)</PRE>
<DL>
<DD>Converts carriage returns and new lines in a string into \r and \n.
 Backquotes the following characters: ` " \ \t and %
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>string</CODE> - the string
<DT><B>Returns:</B><DD>the converted string<DT><B>See Also:</B><DD><A HREF="../../weka/core/Utils.html#unbackQuoteChars(java.lang.String)"><CODE>unbackQuoteChars(String)</CODE></A></DL>
</DD>
</DL>
<HR>

<A NAME="convertNewLines(java.lang.String)"><!-- --></A><H3>
convertNewLines</H3>
<PRE>
public static java.lang.String <B>convertNewLines</B>(java.lang.String&nbsp;string)</PRE>
<DL>
<DD>Converts carriage returns and new lines in a string into \r and \n.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>string</CODE> - the string
<DT><B>Returns:</B><DD>the converted string</DL>
</DD>
</DL>
<HR>

<A NAME="revertNewLines(java.lang.String)"><!-- --></A><H3>
revertNewLines</H3>
<PRE>
public static java.lang.String <B>revertNewLines</B>(java.lang.String&nbsp;string)</PRE>
<DL>
<DD>Reverts \r and \n in a string into carriage returns and new lines.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>string</CODE> - the string
<DT><B>Returns:</B><DD>the converted string</DL>
</DD>
</DL>
<HR>

<A NAME="partitionOptions(java.lang.String[])"><!-- --></A><H3>
partitionOptions</H3>
<PRE>
public static java.lang.String[] <B>partitionOptions</B>(java.lang.String[]&nbsp;options)</PRE>
<DL>
<DD>Returns the secondary set of options (if any) contained in
 the supplied options array. The secondary set is defined to
 be any options after the first "--". These options are removed from
 the original options array.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>options</CODE> - the input array of options
<DT><B>Returns:</B><DD>the array of secondary options</DL>
</DD>
</DL>
<HR>

<A NAME="unbackQuoteChars(java.lang.String)"><!-- --></A><H3>
unbackQuoteChars</H3>
<PRE>
public static java.lang.String <B>unbackQuoteChars</B>(java.lang.String&nbsp;string)</PRE>
<DL>
<DD>The inverse operation of backQuoteChars().
 Converts back-quoted carriage returns and new lines in a string 
 to the corresponding character ('\r' and '\n').
 Also "un"-back-quotes the following characters: ` " \ \t and %
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>string</CODE> - the string
<DT><B>Returns:</B><DD>the converted string<DT><B>See Also:</B><DD><A HREF="../../weka/core/Utils.html#backQuoteChars(java.lang.String)"><CODE>backQuoteChars(String)</CODE></A></DL>
</DD>
</DL>
<HR>

<A NAME="splitOptions(java.lang.String)"><!-- --></A><H3>
splitOptions</H3>
<PRE>
public static java.lang.String[] <B>splitOptions</B>(java.lang.String&nbsp;quotedOptionString)
                                       throws java.lang.Exception</PRE>
<DL>
<DD>Split up a string containing options into an array of strings,
 one for each option.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>quotedOptionString</CODE> - the string containing the options
<DT><B>Returns:</B><DD>the array of options
<DT><B>Throws:</B>
<DD><CODE>java.lang.Exception</CODE> - in case of an unterminated string, unknown character or
                        a parse error</DL>
</DD>
</DL>
<HR>

<A NAME="joinOptions(java.lang.String[])"><!-- --></A><H3>
joinOptions</H3>
<PRE>
public static java.lang.String <B>joinOptions</B>(java.lang.String[]&nbsp;optionArray)</PRE>
<DL>
<DD>Joins all the options in an option array into a single string,
 as might be used on the command line.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>optionArray</CODE> - the array of options
<DT><B>Returns:</B><DD>the string containing all options.</DL>
</DD>
</DL>
<HR>

<A NAME="forName(java.lang.Class, java.lang.String, java.lang.String[])"><!-- --></A><H3>
forName</H3>
<PRE>
public static java.lang.Object <B>forName</B>(java.lang.Class&nbsp;classType,
                                       java.lang.String&nbsp;className,
                                       java.lang.String[]&nbsp;options)
                                throws java.lang.Exception</PRE>
<DL>
<DD>Creates a new instance of an object given it's class name and
 (optional) arguments to pass to it's setOptions method. If the
 object implements OptionHandler and the options parameter is
 non-null, the object will have it's options set. Example use:<p>

 <code> <pre>
 String classifierName = Utils.getOption('W', options);
 Classifier c = (Classifier)Utils.forName(Classifier.class,
                                          classifierName,
                                          options);
 setClassifier(c);
 </pre></code>
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>classType</CODE> - the class that the instantiated object should
 be assignable to -- an exception is thrown if this is not the case<DD><CODE>className</CODE> - the fully qualified class name of the object<DD><CODE>options</CODE> - an array of options suitable for passing to setOptions. May
 be null. Any options accepted by the object will be removed from the
 array.
<DT><B>Returns:</B><DD>the newly created object, ready for use.
<DT><B>Throws:</B>
<DD><CODE>java.lang.Exception</CODE> - if the class name is invalid, or if the
 class is not assignable to the desired class type, or the options
 supplied are not acceptable to the object</DL>
</DD>
</DL>
<HR>

<A NAME="info(int[])"><!-- --></A><H3>
info</H3>
<PRE>
public static double <B>info</B>(int[]&nbsp;counts)</PRE>
<DL>
<DD>Computes entropy for an array of integers.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>counts</CODE> - array of counts
<DT><B>Returns:</B><DD>- a log2 a - b log2 b - c log2 c + (a+b+c) log2 (a+b+c)
 when given array [a b c]</DL>
</DD>
</DL>
<HR>

<A NAME="smOrEq(double, double)"><!-- --></A><H3>
smOrEq</H3>
<PRE>
public static boolean <B>smOrEq</B>(double&nbsp;a,
                             double&nbsp;b)</PRE>
<DL>
<DD>Tests if a is smaller or equal to b.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>a</CODE> - a double<DD><CODE>b</CODE> - a double</DL>
</DD>
</DL>
<HR>

<A NAME="grOrEq(double, double)"><!-- --></A><H3>
grOrEq</H3>
<PRE>
public static boolean <B>grOrEq</B>(double&nbsp;a,
                             double&nbsp;b)</PRE>
<DL>
<DD>Tests if a is greater or equal to b.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>a</CODE> - a double<DD><CODE>b</CODE> - a double</DL>
</DD>
</DL>
<HR>

<A NAME="sm(double, double)"><!-- --></A><H3>
sm</H3>
<PRE>
public static boolean <B>sm</B>(double&nbsp;a,
                         double&nbsp;b)</PRE>
<DL>
<DD>Tests if a is smaller than b.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>a</CODE> - a double<DD><CODE>b</CODE> - a double</DL>
</DD>
</DL>
<HR>

<A NAME="gr(double, double)"><!-- --></A><H3>
gr</H3>
<PRE>
public static boolean <B>gr</B>(double&nbsp;a,
                         double&nbsp;b)</PRE>
<DL>
<DD>Tests if a is greater than b.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>a</CODE> - a double<DD><CODE>b</CODE> - a double</DL>