c++ - 在两个节点上 boost ptree 迭代

Question

我有一个这样的xml

<examples>
<example>
<test name="img">testme</test>
<test name="img1">testme1</test>
<test name="img1">testme2</test>
</example>
<example>
<test name="text">testme</test>
<test name="text">testme1</test>
<test name="text">testme2</test>
</example>
</examples>

我试过这段代码，它只提取第一个示例节点

ptree ptree;
        read_xml(doc_path, ptree);

        BOOST_FOREACH(ptree::value_type & value, ptree.get_child("examples.example")){
           cout<<value.second.get("<xmlattr>.name", "")<<endl;
           cout<<value.second.data()<<endl;

Answer 1

ptree.equal_range 方法具有您正在寻找的行为。请注意，我有几个 C++11 的片段——你需要一个现代编译器。

#include <boost/property_tree/ptree.hpp>
#include <boost/property_tree/xml_parser.hpp>
#include <sstream>

const char xml[] = R"(<examples>
<example>
<test name="img">testme</test>
<test name="img1">testme1</test>
<test name="img1">testme2</test>
</example>
<example>
<test name="text">testme</test>
<test name="text">testme1</test>
<test name="text">testme2</test>
</example>
</examples>)";


int main(int argc, char **argv)
{

    boost::property_tree::ptree ptree;
    std::istringstream xml_str(xml);
    read_xml(xml_str, ptree);

    auto example_range = ptree.get_child("examples").equal_range("example");

    for( auto it = example_range.first; it != example_range.second; ++it )
    {
        auto test_range = it->second.equal_range("test");
        for( auto test_it = test_range.first; test_it != test_range.second; ++test_it )
        {
            std::cout << test_it->second.get("<xmlattr>.name","") <<std::endl;
            std::cout << test_it->second.data() << std::endl;
        }
    }

    return 0;
}