Java中的Iterator是一种fail-fast的设计。 当Iterator迭代一个容器的时候,如果此时有别的方法在更改Collection(容器)的内容,那么Iterator就会抛出 ConcurrentModificationException 。正如官方文档中反复强调的: Thus, in the face of concurrent modification, the
下面就ArrayList的Iterator实现来分析,其实如果我们理解了ArrayList、Hashset、TreeSet的数据结构,内部实现,对于他们是如何实现Iterator也会胸有成竹的。因为ArrayList的内部实现采用数组,所以我们只需要记录相应位置的索引即可,其方法的实现比较简单。 ArrayList的Iterator实现 在ArrayList内部首先是定义一个内部类Itr,该内部类...
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){ }; packagecom.oracle.demo01;importjava.util.ArrayList;importjava.util.Collect...
This method can be called only once per call to next(). The behavior of an iteratorisunspecifiedifthe underlying collectionismodifiedwhilethe iterationisinprogressinany way other than by callingthismethod. 译:从底层集合中移除此迭代器返回的最后一个元素(可选操作)。 每次调用next()时,只能调用此方法...
An iterator over a collection.Iteratortakes the place ofEnumerationin the Java Collections Framework. Iterators differ from enumerations in two ways: Iterators allow the caller to remove elements from the underlying collection during the iteration with well-defined semantics. ...
In this tutorial, we will learn about the Java Iterator interface with the help of an example. All the Java collections include an iterator() method. This method returns an instance of iterator used to iterate over elements of collections.
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() or previous(). This interface is a member of the Java Collections Framework.Since...
Next() Returns the next element in the iteration. Remove() Removes from the underlying collection the last element returned by this iterator (optional operation). SetJniIdentityHashCode(Int32) Set the value returned by JniIdentityHashCode. (Inherited from IJavaPeerable) SetJniManagedPeerState(...
print('next:', '__next__' in dir(l1)) out: *** 判断字符串iter、getitem、next *** iter: True getitem: True next: False *** 判断列表iter、getitem、next *** iter: True getitem: True next: False 1. 2. 3. 4. 5. 6. 7....
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