删除list中不满足条件的数据

从头遍历list的话每一次删除数据下标对应的数据会发生变化

1.从尾部往前遍历

package intership;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

/**
 * @Author: yf.zuo
 * @Date: 12:38 2018/8/20
 */
public class IteratorTest {
    public static void main(String[] args) {
        List<String> list = new ArrayList<>();
        list.add("a");
        list.add("a");
        list.add("a");
        for (int i = list.size()-1; i >=0; i-- ) {
            if (list.get(i).equals("a")) {
                list.remove(i);
                if (list.isEmpty()) {
                    break;
                }
            }
        }
        if (list.isEmpty()) {
            System.out.println("null");
        } else {
            for (String str : list) {
                System.out.println(str);
            }
        }
        
    }
}

2.利用迭代器遍历

package intership;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

/**
 * @Author: yf.zuo
 * @Date: 12:38 2018/8/20
 */
public class IteratorTest {
    public static void main(String[] args) {
        List<String> list = new ArrayList<>();
        list.add("a");
        list.add("a");
        list.add("b");

        Iterator iterator = list.iterator();
        while (iterator.hasNext()){
            if (iterator.next().equals("a")){
                iterator.remove();
            }
        }
        if (list.isEmpty()) {
            System.out.println("null");
        } else {
            for (String str : list) {
                System.out.println(str);
            }
        }

    }
}