List精讲(Java版)·算法常用集合处理方法

List精讲(Java版)·算法常用集合处理方法

请仔细查阅每一个注释：

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class ListFun {

public static void main(String[] args) {
	List<Integer> list=new ArrayList<Integer>();
	//增加
	list.add(222);	list.add(111);	list.add(777);	list.add(600);list.add(220);
	System.out.println("初始状态:");
	for (Integer integer : list) {
		System.out.print(integer+",");
	}
	System.out.println();
	//特别备注·算法中最常用的交换
	Collections.swap(list,2,3);
	System.out.println("交换后状态:");
	for (Integer integer : list) {
		System.out.print(integer+",");
	}
	System.out.println();
	//修改·将下角标为2的值改为666
	list.set(2, 666);
	//移除下角标为3的值
	Integer re = list.remove(3);
	System.out.println("返回所移除的值"+re);
	//foreach直接遍历·排序前
	System.out.println("初始状态:");
	for (Integer integer : list) {
		System.out.print(integer+",");
	}
	System.out.println();
	//List自然排序
	Collections.sort(list);
	System.out.println("自然排序:");
	//foreach直接遍历·排序后
	for (Integer integer : list) {
		System.out.print(integer+",");
	}
	System.out.println();
	//注reverse是反向输出，不是倒序
	Collections.reverse(list);
	System.out.println("倒序输出:");
	for (Integer integer : list) {
		System.out.print(integer+",");
	}
	System.out.println();
	//随机排序
	Collections.shuffle(list);
	System.out.println("随机排序:");
	for (Integer integer : list) {
		System.out.print(integer+",");
	}
	System.out.println();
	//根据下标获取，可以使用fori来遍历
	System.out.println("get(下标):"+list.get(2));
	//判断是否存在某值
	boolean contains = list.contains(666);
	System.out.println(contains?"存在666":"不存在666");
	List<Integer> subList = list.subList(1, 3);
	//截取后增加一个250
	subList.add(250);
	System.out.println("截取后的集合(不建议使用):");
	for (Integer integer : subList) {
		System.out.print(integer+",");
	}
	System.out.println("原集合状态:(被动增加了250)");
	for (Integer integer : list) {
		System.out.print(integer+",");
	}
	/**
	 * list所常用的方法分享完毕
	 */
	
}
}

打印效果：