带有属性树的boost xml c ++简单解析 [英] c++ simple parse with boost xml with property tree

问题描述

我对boost xml解析有这个问题:

I have this question about the boost xml parsing:

这是我的Xml片段:

<Clients>
  <Client name="Alfred" />
  <Client name="Thomas" />
  <Client name="Mark" />
</Clients>

然后我用以下代码读取名称:

and I read the name with this code:

std::string name = pt.get<std::string>("Clients.Client.<xmlattr>.name, "No name");

并且工作正常，但始终检索第一个节点.

and works fine, but retrieve always the first node..

有没有办法获得第二个，第三个节点而不循环?

Is there a way to get the second, third node without looping?

谢谢

推荐答案

在属性树中无法查询多值键. (部分原因是大多数受支持的后端格式都不正式支持重复密钥.)

There's no facility to query multi-valued keys in Property Tree. (Partly because most of the supported backend formats do not officially support duplicate keys).

但是，您可以遍历子元素，因此可以实现自己的查询，如下所示:

However, you can iterate through child elements, so you can implement your own query, like so:

for (auto& child : pt.get_child("Clients"))
    if (child.first == "Client")
        std::cout << child.second.get<std::string>("<xmlattr>.name", "No name") << "\n";

请参阅完整的示例 在Coliru上直播 :

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

using boost::property_tree::ptree;

int main()
{
    std::stringstream ss("<Clients>\n"
        "  <Client name=\"Alfred\" />\n"
        "  <Client name=\"Thomas\" />\n"
        "  <Client name=\"Mark\" />\n"
        "</Clients>");

    ptree pt;
    boost::property_tree::read_xml(ss, pt);

    for (auto& child : pt.get_child("Clients"))
    {
        if (child.first == "Client")
            std::cout << child.second.get<std::string>("<xmlattr>.name", "No name") << "\n";
    }
};

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