使用foreach在Java中迭代并行数组的巧妙方式 [英] Nifty way to iterate over parallel arrays in Java using foreach

问题描述

我继承了大量的代码，广泛使用并行数组来存储键/值对。这样做实际上是有道理的，但是编写遍历这些值的循环是有点尴尬的。我真的很喜欢新的Java的foreach结构，但似乎没有一种方法可以用这个方法遍历并行列表。
$ b $ p

使用正常的 for 循环，我可以很容易地做到这一点：

  for（int i = 0; i< ; list1.length; ++ i）{
 doStuff（list1 [i]）; 
 doStuff（list2 [i]）; 
 
 
 
 
 
 $ b但是在我看来，这不是纯粹的语义，因为我们没有检查在迭代期间 list2 的范围。有没有一些聪明的语法类似的for-每个我可以使用平行列表？
解决方案
我会使用一个 Map 我自己。但是，在你的说法中，一对数组在你的情况下是有意义的，那么一个实用方法如何处理你的两个数组并返回一个 Iterable 包装器？
 
 
 
概念上：
 
 pre $  for（Pair< K，V> p：wrap（list1 ，list2））{
 doStuff（p.getKey（））; 
 doStuff（p.getValue（））; 
 
 
 
 
 
 
  Iterable > ;  wrapper会隐藏边界检查。
 
I've inherited a bunch of code that makes extensive use of parallel arrays to store key/value pairs. It actually made sense to do it this way, but it's sort of awkward to write loops that iterate over these values. I really like the new Java foreach construct, but it does not seem like there is a way to iterate over parallel lists using this.

With a normal for loop, I can do this easily:
for (int i = 0; i < list1.length; ++i) {
    doStuff(list1[i]);
    doStuff(list2[i]);
}
But in my opinion this is not semantically pure, since we are not checking the bounds of list2 during iteration. Is there some clever syntax similar to the for-each that I can use with parallel lists?
解决方案
I would use a Map myself. But taking you at your word that a pair of arrays makes sense in your case, how about a utility method that takes your two arrays and returns an Iterable wrapper?

Conceptually:
for (Pair<K,V> p : wrap(list1, list2)) {
    doStuff(p.getKey());
    doStuff(p.getValue());
}
The Iterable<Pair<K,V>> wrapper would hide the bounds checking.

                        
这篇关于使用foreach在Java中迭代并行数组的巧妙方式的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！