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无法读取嵌套映射(引发yaml::invalidscalar)

yaml-cpp

1

Robert Boehne · 技术社区 · 16 年前

我有一个类(包含一些标量值和浮点向量),我想读写一个实例作为另一个映射的值。

    
// write

 out << YAML::Key << "my_queue" << YAML::Value << my_queue;



// read (other code cut out...)
 for (YAML::Iterator it=doc.begin();it!=doc.end();++it)
  {
    std::string key, value;
    it.first() >> key;
    it.second() >> value;
    if (key.compare("my_queue") == 0) {
      *it >> my_queue;
    }
 }

Writing this class works perfectly, but I can't seem to read it no matter what I do. It keeps throwing an InvalidScalar.

Caught YAML::InvalidScalar  yaml-cpp: error at line 20, column 13: invalid scalar

这就是输出(用yaml cpp编写而不报告任何错误)如下所示:

Other Number: 80
my_queue:
  size: 20
  data:
    - 3.5
    - -1
    - -1.5
    - 0.25
    - -24.75
    - -5.75
    - 2.75
    - -33.55
    - 7.25
    - -11
    - 15
    - 37.5
    - -3.75
    - -28.25
    - 18.5
    - 14.25
    - -36.5
    - 6.75
    - -0.75
    - 14
  max_size: 20
  mean: -0.0355586
  stdev: 34.8981
even_more_data: 1277150400

文档似乎说这是支持的用法,一个嵌套的映射,在本例中,序列作为值之一。它抱怨它是一个无效的标量,即使我做的第一件事是告诉它这是一个映射:

YAML::Emitter& operator << ( YAML::Emitter& out, const MeanStd& w )
{
  out << YAML::BeginMap;
  out << YAML::Key << "size";
  out << YAML::Value << w.size();

  out << YAML::Key << "data";
  out << YAML::Value << YAML::BeginSeq;
  for(Noor::Number i=0; i<w.size(); ++i) {
    out << w[i];
  }
  out << YAML::EndSeq;
  out << YAML::Key << "max_size";
  out << YAML::Value << w.get_max_size();
  out << YAML::Key << "mean";
  out << YAML::Value << w.mean();
  out << YAML::Key << "stdev";
  out << YAML::Value << w.stdev();

  out << YAML::EndMap;
  return out;
}

有人看到这个问题吗?

1 回复 | 直到 16 年前

1

Jesse Beder 16 年前

当你读山药时:

std::string key, value;
it.first() >> key;
it.second() >> value; // ***
if (key.compare("my_queue") == 0) {
  *it >> my_queue;
}

标记的行试图读取价值作为标量的键/值对( std::string )这就是为什么它告诉你它是一个无效的标量。相反,您需要:

std::string key, value;
it.first() >> key;
if (key.compare("my_queue") == 0) {
  it.second() >> my_queue;
} else {
  // ...
  // for example: it.second() >> value;
}