我们是否需要在ArrayList上使用迭代器？ [英] Do we ever need to use Iterators on ArrayList?

问题描述

昨天，当我回答问题使用迭代器并删除时出现ConcurrentModificationException错误我添加了一条通知

Yesterday, when I was answering to question getting ConcurrentModificationException error while using iterator and remove I added a notice that

当你有ArrayLists时使用迭代器不是一个好主意。

It's not a good idea to use iterators when you have ArrayLists.

你不需要深刻理解那个问题就可以回答。

You do not need to deeply understand that question to answer on that one.

在那里，我得到两条评论，我错了。

There, I got two comments that I'm wrong.

我的论点：

1. 迭代器的代码可读性差得多。

1. The code is much less readable with iterators.

有可能引发难以调试的ConcurrentModificationException。

There is a possibility to raise ConcurrentModificationException that is hard to debug.

你能解释一下吗？

问题：
我们是否需要在ArrayList上使用Iterators？

Question: Do we ever need to use Iterators on ArrayList?

UPD

这是关于明确使用Iterator。

This is about explicitly using Iterator.

推荐答案

很有用使用ArrayLists的迭代器的情况是在迭代时要删除元素的时候。您只有三个安全的解决方案：

A big use case of iterators with ArrayLists is when you want to remove elements while iterating. You have only three safe solutions :

• 使用迭代器及其删除方法


• 将要保留的元素复制到另一个列表中


• 带索引的丛林

• use an iterator and its remove method
• copy the elements you want to keep in another list
• jungle with indexes

假设你在迭代时没有添加，使用迭代器是避免 ConcurrentModificationException 。

Assuming you don't add while iterating, using the iterator is a mean to avoid the ConcurrentModificationException.

可读性参数是主观的。我个人认为没有一个干净的声明迭代器可读性较差。并且它并不重要，因为迭代器是同时迭代和删除的安全方式。

The readability argument is subjective. Personally I don't find a cleanly declared iterator less readable. And it doesn't really matter as the iterator is the safe way to iterate and remove at the same time.

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