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：