今天写了个简单的list中remove元素的方法,结果报错。。。
List<String> ll = Arrays.asList("1","2","3","4","5"); for (int i=0; i < ll.size(); i++){ ll.remove(i); }
报错,java.lang.UnsupportedOperationException,这个是因为Arrays.asList()返回AbstractList,没有实现增删改操作,用如下构造方式解决。
List<String> list = new ArrayList<>(Arrays.asList("1","2","3","4","5")); for (int i = 0; i < list.size(); i++){ list.remove(i); } System.out.println(list);
注意这种方式并不是把所有元素删除(list.size())
list = new ArrayList<>(Arrays.asList("1","2","3","4","5")); for (String s : list){ list.remove(s); } System.out.println(list);
报错,java.util.ConcurrentModificationException,这个是因为for-each迭代过程中掺杂了修改元素的动作。