ranges::to() 错误：请求转换为非标量类型

Question

#include <ranges>
#include <algorithm>
#include <vector>
using namespace std;

struct Edge{int from, to;};

const vector<int> v1 = {1, 1} , v2 = {2,2};

vector<Edge> v3 = views::zip( v1, v2) | ranges::to<vector>();

使用 g++14 编译。

prog.cc:10:38：错误：请求从“向量，分配器>>”转换为非标量类型“向量”

这个问题可以不做就解决吗（冗长得令人痛苦）：

#include <ranges>
#include <algorithm>
#include <vector>
using namespace std;

int main(){

struct Edge{int from, to;};

const vector<int> v1 = {1, 1} , v2 = {2,2};

vector<Edge> v3 = views::zip( v1, v2) | views::transform([](const auto arg){const auto [a, b]=arg; return Edge{a,b};}) | ranges::to<vector>();

}

Answer 1

C++23 带来了 zip_transform，它可以将其简化为这样

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

//using namespace std; //unlearn this

int main()
{

    struct Edge
    {
        static Edge Create(int f,int t)
        {
            return Edge{f,t};
        }

        int from;
        int to;
    };

    const std::vector<int> v1 = { 1, 2 };
    const std::vector<int> v2 = { 3, 4 };
    
    auto edges = std::views::zip_transform(Edge::Create,v1,v2) | std::ranges::to<std::vector>();

    for(const auto& edge : edges)
    {
        std::cout << "edge : from " << edge.from << " to" << edge.to << "\n";
    }

    return 0;
}