Use nlohmann json to unpack list of integers to a std::vector<int>

I'm using nlohman::json.

It's awesome, but is there any way to unpack:

{
    "my_list" : [1,2,3]
}

into a std:vector<int> ?

I can't find any mention in the docs, and std::vector<int> v = j["my_list"]; fails, as does j["my_list"].get<std::vector<int>>().

Crosslinking to https://github.com/nlohmann/json/issues/1460

Actually it does work. I had not isolated a test case, and my JSON string was malformed.

So,

json J(json_string);
J["my_list"].get<std::vector<int>>()

does work.

In my case I make sure my C++ variable names match the JSON keys, so I can simply use the macro:

#define EXTRACT(x) x = J[#x].get< decltype(x) >()

int foo;
std::vector<float> bar;

EXTRACT(foo);
EXTRACT(bar);

Or better: use get_to() since 3.3.0 to deduce the type directly. Reference

Live demo: https://godbolt.org/z/YWPdrvd7c

#include <vector>
#include <iostream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;


int main(){
    json j = json::parse(R"({"my_list" : [1,2,3]})");

    std::cout << "json" << j << "\n";

    std::vector<int> v;
    j["my_list"].get_to(v);

    std::cout << "items: ";
    for(auto item:v){
        std::cout << item << ", ";
    }
}