Iterator类位于java.util包中，使用前要先引入，以下是其语法格式：import java.util.Iterator; // 引入 Iterator 类 2、获取一个迭代器 可以使用Iterator()方法在集合中获取一个迭代器，示例如下：// 引入 ArrayList 和 Iterator 类 import java.util.ArrayList;import java.
TypeError:'Counter'object is not iterable 错误显示说:这个Counter对象不是可迭代的!这是什么意思呢? 原来,为了使用这个for..in 迭代语法糖,我们需要在in后面放可以迭代的“迭代器”,什么是可以迭代?你可以认为就是可以使用for..in语法糖,让语法糖帮你重复调用next方法就好了。如果不可以迭代, 那么for..in这个...
ConcurrentModificationException官方文档第一句就指出: This exception may be thrown by methods that have detected concurrent modification of an object when such modification is not permissible. 这时候可以采用java.util.concurrent包下面的线程安全的容器解决此异常。 最后要说的是,ConcurrentModificationException应该...
Skip navigation links Java SE 17 & JDK 17 Overview Module Package Class Use Tree Preview New Deprecated Index Help Summary: Nested | Field | Constr | Method Detail: Field | Constr | Method SEARCH: Module java.base Package java.util Interface Iterator<E> Type Parameters: E - the type of ...
Object[] elementData = ArrayList.this.elementData;if (i >=elementData.length)thrownewConcurrentModificationException(); cursor = i + 1;return (E) elementData[lastRet =i]; } 在next()方法中有一个checkForComodification()方法,其实现为: finalvoidcheckForComodification() ...
/*** Tests whether the iterator has a next object.* @return true if there are further objects, false otherwise*/publicbooleanhasNext(){returnj<size;}// size is field of outer instance/*** Returns the next object in the iterator.** @return next object* @throws NoSuchElementException if ...
An Iterator is an object that can be used to loop through collections, like ArrayList and HashSet. It is called an "iterator" because "iterating" is the technical term for looping.To use an Iterator, you must import it from the java.util package....
Object obj=it.next();if("three".equals(obj)){ it.add("four");//[one, two, three, four, five]//it.set("3");//[one, two, 3, five]//对比输出结果} } System.out.println(list); } } 2、增强for循环: (1)for(元素的数据类型 变量:Collection集合or数组){ }; ...
boolean remove(Object o); 1. 从该集合中删除指定元素的单个实例(如果存在)(可选操作)。 如果该集合中有多个相同元素,则删除第一个。删除元素后,后面的元素会往前移。返回值为布尔型。 boolean equals(Object o); 1. 将指定的对象与此集合进行比较以获得相等性。 返回值为布尔型。
text/java 复制 Element(0) Element(1) Element(2) ... Element(n-1) cursor positions: ^ ^ ^ ^ ^ Note that the #remove and #set(Object) methods are not defined in terms of the cursor position; they are defined to operate on the last element returned by a call to #next ...