Standard Library Views

Converting a View Back to a Standard Container

How can I convert a view back to a standard container like std::vector?

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Converting a view back to a standard container like std::vector is straightforward. You can use the range-based constructor of std::vector to achieve this.

Here’s an example:

#include <iostream>
#include <ranges>
#include <vector>

int main() {
  std::vector<int> Numbers{1, 2, 3, 4, 5};
  auto View = std::views::take(Numbers, 3);

  std::vector<int> NewContainer(
    View.begin(), View.end());

  for (int Num : NewContainer) {
    std::cout << Num << ", ";
  }
}
1, 2, 3,

Explanation

  • Create View: We create a view of the first three elements using std::views::take().
  • Convert to std::vector: We use the range-based constructor of std::vector to initialize NewContainer with the elements of the view.
  • Output: We then iterate over the new container to display its elements.

Advantages

  • Efficiency: This method efficiently copies elements from the view to the new container.
  • Simplicity: It leverages existing C++ mechanisms for range-based initialization.

This approach can be adapted to other standard containers, such as std::list or std::deque, using their range-based constructors in a similar manner.

For example, converting to a std::list:

#include <iostream>
#include <list>
#include <ranges>
#include <vector>

int main() {
  std::vector<int> Numbers{1, 2, 3, 4, 5};
  auto View = std::views::take(Numbers, 3);

  std::list NewContainer(View.begin(), View.end());

  for (int Num : NewContainer) {
    std::cout << Num << ", ";
  }
}
1, 2, 3,

Using this method, you can easily convert views back to any standard container type, preserving the benefits of views while enabling further manipulations or storage as needed.

Answers to questions are automatically generated and may not have been reviewed.

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