迭代时从向量中删除项目?

2022-01-07 00:00:00 iterator c++ stl

我有一个向量，其中包含活动或非活动的项目.我希望此向量的大小保持较小以解决性能问题，因此我希望从向量中删除已标记为非活动的项目.我在迭代时尝试这样做，但我收到错误向量迭代器不兼容".

I have a vector that holds items that are either active or inactive. I want the size of this vector to stay small for performance issues, so I want items that have been marked inactive to be erased from the vector. I tried doing this while iterating but I am getting the error "vector iterators incompatible".

vector<Orb>::iterator i = orbsList.begin();

    while(i != orbsList.end()) {
        bool isActive = (*i).active;

        if(!isActive) {
            orbsList.erase(i++);
        }
        else {
            // do something with *i
            ++i;
        }
    }

推荐答案

过去我做过的最易读的方法是使用 std::vector::erase 结合 std::remove_if.在下面的示例中，我使用此组合从向量中删除任何小于 10 的数字.

The most readable way I've done this in the past is to use std::vector::erase combined with std::remove_if. In the example below, I use this combination to remove any number less than 10 from a vector.

(对于非 c++0x，您可以将下面的 lambda 替换为您自己的谓词:)

// a list of ints
int myInts[] = {1, 7, 8, 4, 5, 10, 15, 22, 50. 29};
std::vector v(myInts, myInts + sizeof(myInts) / sizeof(int));

// get rid of anything < 10
v.erase(std::remove_if(v.begin(), v.end(), 
                       [](int i) { return i < 10; }), v.end());

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