nlohmann的json库将数组转换为结构向量 [英] nlohmann's json library convert an array to a vector of structs

问题描述

说我有一个看起来像这样的json数组:

Say I have a json array that looks like this:

[
  {
    "Name": "test",
    "Val": "test_val"
  },
  {
    "Name": "test2",
    "Val": "test_val2"
  }
]

我想将其转换为结构向量:

I want to convert this into a vector of structs:

struct Test {
  string Name;
  string Val;
};

我了解json.get<>()方法，但是不知道如何将其应用于此方法.

I know about the json.get<>() method, but do not know how to apply that to this.

推荐答案

要使自动get<>起作用，您需要在JSON和结构之间提供一个映射:

For the automatic get<> to work, you need to provide a mapping between JSON and your struct:

void from_json(const nlohmann::json& j, Test& p) {
    j.at("Name").get_to(p.Name);
    j.at("Val").get_to(p.Val);
}

然后它将按预期工作.

auto parsed = json.get<std::vector<Test>>();

演示: https://godbolt.org/z/9P1mjO

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