保持数据的迭代器的向量 [英] Keeping vector of iterators of the data

问题描述

我有一个函数：

  void get_good_items（const std :: vector< T>& data，std ::向量< XXX>& good_items）; 
  

此函数应检查所有数据并查找满足条件的项，并返回

什么是最好的，而不是 XXX ？

1. std :: vector< size_t> 包含所有好的索引。


2. 
   
3. std： std :: vector< T *> ：vector< std :: vector< T> :: iterator> 包含对项目的迭代器。


4. 其他？

编辑：

> good_items ？
许多东西...其中一个是从向量中删除它们并将它们保存在其他位置。

其中最重要的是我是如何访问数据中的项目将快速取决于 good_items ？的结构？

编辑3：

我刚刚重申我的想法是错误的。不是最好保持原始指针（或聪明）作为向量的项目，所以我可以保持向量的真正的价值观（它们是指针），我不害怕重复，因为他们只是指针？

解决方案

如果从原始向量中删除项目，您列出的每个方法都会有问题。

如果将项目添加到原始向量中，第二个和第三个将是有问题的。如果使用 push_back 添加项目，第一个不会有问题。

因此，我建议使用 std :: vector< size_t> 。

I have a function :

void get_good_items(const std::vector<T>& data,std::vector<XXX>& good_items);

This function should check all data and find items that satisfies a condition and return where they are in good_items.

what is best instead of XXX?

1. std::vector<size_t> that contains all good indices.
2. std::vector<T*> that contain a pointers to the items.
3. std::vector<std::vector<T>::iterator> that contains iterators to the items.
4. other ??

EDIT:

What will I do with the good_items? Many things... one of them is to delete them from the vector and save them in other place. maybe something else later

EDIT 2:

One of the most important for me is how will accessing the items in data will be fast depending on the struct of good_items?

EDIT 3:

I have just relized that my thought was wrong. Is not better to keep raw pointers(or smart) as items of the vector so I can keep the real values of the vector (which are pointers) and I do not afraid of heavy copy because they are just pointers?

解决方案

If you remove items from the original vector, every one of the methods you listed will be a problem.

If you add items to the original vector, the second and third will be problematic. The first one won't be a problem if you use push_back to add items.

All of them will be fine if you don't modify the original vector.

Given that, I would recommend using std::vector<size_t>.

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