Java 如何获取列表中特定项的最后一个索引？

如何获取特定shipId列表中最后添加的项目。Fox示例shipId1最后添加的项目在这里

[shipID:1 position:30]

一个简单的实现是检查所需项目的任何出现情况，然后迭代获取所需项目的索引，如果找到新的索引，则覆盖以前的索引。在末尾返回此索引

[shipID: 1 position: 10]
[shipID: 1 position: 20]
[shipID: 2 position: 10]
[shipID: 1 position: 30]
[shipID: 2 position: 20]

---

编辑以添加检查列表中是否不存在“desiredStringToCheck”（感谢Tom！）。

您可以使用

列表迭代器反向迭代数据：

for (int i = (ships.size() - 1); i >= 0; i--) {
    if (ships.get(i).equals("desiredStringToCheck") {  //it may not necessarily be a string
        return i;
    }
}
return -1;       //If it doesn't return in the loop, meaning the string is not in the list

然后只需使用
List.lastIndexOf
：

public class Ship
{
   private int shipId;
   private int position;

   @Override public int hashCode() {
     return Objects.hashCode(shipId, position);
   }

   @Override public boolean equals(Object other) {
     if (other == this) {
       return true;
     }
     if (other instanceof Ship) {
       Ship o = (Ship) other;
       return shipId == o.shipId && position == o.position;
     }
     return false;
   }
}

你想过这个问题吗？谢谢！这就行了！是的，这是一节课。所以他需要写几个getter。为什么不向后迭代，找到匹配的事件后返回呢。。我没想到。现在将使用向后迭代更新我的解决方案。谢谢Andy。如果找不到搜索的元素，是否确实要返回索引
0
？
for (int i = (ships.size() - 1); i >= 0; i--) {
    if (ships.get(i).equals("desiredStringToCheck") {  //it may not necessarily be a string
        return i;
    }
}
return -1;       //If it doesn't return in the loop, meaning the string is not in the list

ListIterator<Ship> it = ships.listIterator(ships.size());
while (it.hasPrevious()) {
  int index = it.previousIndex();
  Ship previous = it.previous();
  if (/* somehow compare previous to the thing you are looking for */) {
    return index;
  }
}

public class Ship
{
   private int shipId;
   private int position;

   @Override public int hashCode() {
     return Objects.hashCode(shipId, position);
   }

   @Override public boolean equals(Object other) {
     if (other == this) {
       return true;
     }
     if (other instanceof Ship) {
       Ship o = (Ship) other;
       return shipId == o.shipId && position == o.position;
     }
     return false;
   }
}

ships.lastIndexOf(new Ship(1, 10));