collectionutils.java

这是一个matlab的java实现。里面有许多内容。请大家慢慢捉摸。

/* Copyright (C) 2003 Univ. of Massachusetts Amherst, Computer Science Dept.
   This file is part of "MALLET" (MAchine Learning for LanguagE Toolkit).
   http://www.cs.umass.edu/~mccallum/mallet
   This software is provided under the terms of the Common Public License,
   version 1.0, as published by http://www.opensource.org.  For further
   information, see the file `LICENSE' included with this distribution. */

package edu.umass.cs.mallet.base.util;

import java.util.*;

/**
 *  *
 * Created: Sun Jan 25 01:04:29 2004
 *
 * @author <a href="mailto:[e-mail]">Charles Sutton</a>
 * @version $Id: CollectionUtils.java,v 1.1 2004/07/22 00:37:22 casutton Exp $
 */
public class CollectionUtils {

	private CollectionUtils() {} // No instances
	
	public static String dumpToString (Collection c, String separator)
	{
		String retval = "";
		for (Iterator it = c.iterator(); it.hasNext();) {
			retval += it.next().toString();
			retval += separator;
		}
		return retval;
	}

	public static String dumpToString (Collection c)
	{
		return dumpToString (c, " ");
	}

	public static void print (Collection c) 
	{
		System.out.println (dumpToString (c));
	}

	public static void print (Collection c, String separator) 
	{
		System.out.println (dumpToString (c, separator));
	}

	public static Collection subset (Collection c, int size, java.util.Random rand)
	{
		ArrayList list = new ArrayList (c);
		int realSize = (size < c.size()) ? size : c.size();
		java.util.Collections.shuffle (list, rand);
		return list.subList (0, realSize);
	}

} // Collections