不能将运算符[]与数组的字符串参数一起使用(解析json)

我决定在c++上编写一个用于天气预报的tg机器人,当我需要用json解析字符串时,总是会出现错误(数字有效),在谷歌上搜索了很多,但一无所获。请帮帮我,如果我不明白哪里搞砸了,我就是睡不着。

json库-nlohmann/json( https://github.com/nlohmann/json )

tg api-tgbot cpp( https://github.com/reo7sp/tgbot-cpp )

链接到json- https://api.openweathermap.org/data/2.5/weather?q=London&appid=2e71c3ca54737820fc305ba048331b8c (api密钥是免费的)。

解析器

std::string get_weather(std::string where) {
    nlohmann::json js_obj = nlohmann::json::parse(get_request("https://api.openweathermap.org/data/2.5/weather?q=London&appid=2e71c3ca54737820fc305ba048331b8c"));
    if(where == "London") {
        return js_obj["weather"]["0"]["main"].get<std::string>();;
    }
}

当我调用这个方法来解析字符串时,会出现一个错误。

bot.getApi().sendMessage(query1->message->chat->id, "Weather: " + get_weather("London")); 

terminate called after throwing an instance of 'nlohmann::json_abi_v3_11_3::detail::type_error'
what():  [json.exception.type_error.305] cannot use operator[] with a string argument with array

但有了数字,一切都会好起来

float get_temperature(std::string where) {
    auto js_obj = nlohmann::json::parse(get_request("https://api.openweathermap.org/data/2.5/weather?q=London&appid=2e71c3ca54737820fc305ba048331b8c"));
    if(where == "London") {
        return js_obj["main"]["temp"].get<float>();
    }
}

bot.getApi().sendMessage(query1->message->chat->id, "Temperature in your area: "
                        + std::to_string (get_temperature("London") - 273.15));