yaml-cpp最简单的方法来迭代具有未定义值的映射 [英] yaml-cpp Easiest way to iterate through a map with undefined values

问题描述

我的YAML看起来像这样：

  characterType：
 type1：
 attribute1：something 
 attribute2：something 
 type2：
 attribute1：something 
 attribute2：something 
  

我不知道有多少类型这些键的名称将是什么。这就是为什么我试图迭代地图。

  struct CharacterType {
 std :: string attribute1; 
 std :: string attribute2; 
}; 
 
命名空间YAML {
模板<> 
 struct convert< CharacterType> {
 static bool decode（const Node& node，CharacterType& cType）{
 cType.attribute1 = node [attribute1] as< std :: string& （）; 
 cType.attribute2 = node [attribute2]。as< std :: string>（）; 
 return true; 
} 
}; 
} 
 
 --------------------- 
 std :: vector< CharacterType> cTypeList; 
 
 for（YAML :: const_iterator it = node [characterType]。begin（）; it！= node [characterType]。end（）; ++ it）{
 cTypeList.push_back（it-> as< CharacterType>（））; 
} 
  

前面的代码在编译时没有任何麻烦，我得到这个错误：
terminate抛出 YAML :: TypedBadConversion< CharacterType>

的实例后终止

我也尝试使用子索引而不是迭代器，得到相同的错误。

我确定我做错了，我只是不能

解决方案

迭代地图时，迭代器指向一个键/值对节点，而不是单个节点。例如：

  YAML :: Node characterType = node [characterType]; 
 for（YAML :: const_iterator it = characterType.begin（）; it！= characterType.end（）; ++ it）{
 std :: string key = it-> first.as< std :: string>（）; //<  -  key 
 cTypeList.push_back（it-> second.as< CharacterType>（））; // < -  value 
} 
  

你的代码编译，即使你的节点是一个map节点， YAML :: Node 是有效的动态类型，所以它的迭代器必须（静态）序列迭代器和映射迭代器。）

I'd like to obtain every node in a map without knowing the keys.

My YAML looks like this:

characterType :
 type1 :
  attribute1 : something
  attribute2 : something
 type2 :
  attribute1 : something
  attribute2 : something

I don't know how many "type"s will be declared or what the name of those keys will be. That's why I'm trying to iterate through the map.

struct CharacterType{
  std::string attribute1;
  std::string attribute2;
};

namespace YAML{
  template<>
  struct convert<CharacterType>{
    static bool decode(const Node& node, CharacterType& cType){ 
       cType.attribute1 = node["attribute1"].as<std::string>();
       cType.attribute2 = node["attribute2"].as<std::string>();
       return true;
    }
  };
}

---------------------
std::vector<CharacterType> cTypeList;

for(YAML::const_iterator it=node["characterType"].begin(); it != node["characterType"].end(); ++it){
   cTypeList.push_back(it->as<CharacterType>());
}

The previous code doesn't give any trouble when compiling but then at execution time I get this error: terminate called after throwing an instance of YAML::TypedBadConversion<CharacterType>

I've also tried using a subindex instead of the iterator, getting the same error.

I'm sure I'm doing something wrong, I just can't see it.

解决方案

When you iterate through a map, the iterator points to a key/value pair of nodes, not a single node. For example:

YAML::Node characterType = node["characterType"];
for(YAML::const_iterator it=characterType.begin();it != characterType.end();++it) {
   std::string key = it->first.as<std::string>();       // <- key
   cTypeList.push_back(it->second.as<CharacterType>()); // <- value
}

(The reason that your code compiled, even though your node is a map node, is that YAML::Node is effectively dynamically typed, so its iterator has to act (statically) as both a sequence iterator and a map iterator.)

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