Move few elements from list to a vector

Question

I am planning to move some elements from a list to the target container(say vector) for further processing. Is it safe to use move_iterator for moving to target And erase the moved section of the source container?

#include<list>
#include<vector>
#include<iterator>
struct DataPoint {};
int main() {
    std::list<Datapoint> d_data; // source
    std::vector<Datapoint> v2;   // target
    v2.insert(v2.end(), 
              std::make_move_iterator(d_data.begin()), 
              std::make_move_iterator(d_data.begin() + size)
             );
    d_data.erase(d_data.begin(), d_data.begin() + size);  // safe? necessary?
    //...
    //d_batch->addData(v2);
    return 0;
}

Answer 1

You may find std::move easier to use.

And yes, you do need to erase the moved elements in the source container.

[Demo]

#include <algorithm>  // move
#include <fmt/ranges.h>
#include<list>
#include<vector>
#include<iterator>  // back_inserter

int main() {
    std::list<int> l{1, 2, 3, 4, 5};  // source
    std::vector<int> v;  // target
    auto begin_it{std::next(l.begin())};
    auto end_it{std::prev(l.end())};
    std::move(begin_it, end_it, std::back_inserter(v));
    fmt::print("l before erase: {}\n", l);
    l.erase(begin_it, end_it);
    fmt::print("l after erase: {}\nv: {}\n", l, v);
}

// Outputs:
//
//   l before erase: [1, 2, 3, 4, 5]
//   l after erase: [1, 5]
//   v: [2, 3, 4]