在java中以相反的顺序遍历列表 [英] Iterating through a list in reverse order in java

问题描述

我正在迁移一段代码以使用泛型.这样做的一个论点是，for 循环比跟踪索引或使用显式迭代器要干净得多.

I'm migrating a piece of code to make use of generics. One argument for doing so is that the for loop is much cleaner than keeping track of indexes, or using an explicit iterator.

在大约一半的情况下，今天使用索引以相反的顺序迭代列表(一个 ArrayList).

In about half the cases, the list (an ArrayList) is being iterated in reverse order by using an index today.

有人可以建议一种更简洁的方法吗(因为在处理集合时我不喜欢 indexed for loop)，尽管它确实有效?

Can someone suggest a cleaner way of doing this (since I dislike the indexed for loop when working with collections), though it does work?

 for (int i = nodes.size() - 1; i >= 0; i--) {
    final Node each = (Node) nodes.get(i);
    ...
 }

注意:我不能在 JDK 之外添加任何新的依赖项.

Note: I can't add any new dependencies outside the JDK.

推荐答案

试试这个:

// Substitute appropriate type.
ArrayList<...> a = new ArrayList<...>();

// Add elements to list.

// Generate an iterator. Start just after the last element.
ListIterator li = a.listIterator(a.size());

// Iterate in reverse.
while(li.hasPrevious()) {
  System.out.println(li.previous());
}

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