提取XML属性和节点值R [英] extract XML attributes and node values R

问题描述

我在R中有一个XML文件.该XML文件如下所示:

I have an XML file in R. The XML file looks like this:

rootNode <- xmlRoot(xmlfile)
rootNode[[1]]

<pdv id="1000001" latitude="4620114" longitude="519791" cp="01000" pop="R">
  <adresse>ROUTE NATIONALE</adresse>
  <ville>SAINT-DENIS-LèS-BOURG</ville>
  <ouverture debut="01:00" fin="01:00" saufjour=""/>
  <services>
    <service>Automate CB</service>
    <service>Vente de gaz domestique</service>
    <service>Station de gonflage</service>
  </services>
  <prix nom="Gazole" id="1" maj="2014-01-02 11:08:03" valeur="1304"/>
  <prix nom="SP98" id="6" maj="2014-12-31 08:39:46" valeur="1285"/>
  <prix nom="Gazole" id="1" maj="2007-02-28 07:48:59.315736" valeur="999"/>
  <fermeture/>
  <rupture/>
</pdv> 

rootNode [[2]]是:

the rootNode[[2]] is:

<pdv id="1000002" latitude="4621842" longitude="522767" cp="01000" pop="R">
  <adresse>16 Avenue de Marboz</adresse>
  <ville>BOURG-EN-BRESSE</ville>
  <ouverture debut="08:45" fin="19:30" saufjour="Dimanche"/>
  <services>
    <service>Automate CB</service>
    <service>Vente de gaz domestique</service>
    <service>Station de gonflage</service>
  </services>
  <prix nom="Gazole" id="1" maj="2007-01-02 08:34:29.101626" valeur="995"/>
  <prix nom="Gazole" id="1" maj="2007-01-26 09:49:39.197356" valeur="977"/>
  <fermeture/>
  <rupture/>
</pdv> 

以此类推.

我正在运行下一个代码以获取有关评估者"的信息

I am running the next code to get the information about "valuer"

valeur = xpathApply(rootNode, "//prix", xmlGetAttr, "valeur")
valeur <- data.frame(matrix(unlist(valeur), byrow=T),stringsAsFactors=FALSE)

实际上，我正在获取值"的值，但问题是:我无法确定前三个值属于rootNode [[1]]，而后两个值属于rootNode [[2]]等.

Actually, I am getting the values of "valuer", but the problem is: I can't identify that the three first values belong to rootNode[[1]] and the last two values belong to rootNode[[2]] and so on.

如何创建一个变量，该变量指示三个第一个值属于rootNode [[1]]，另外两个属于rootNode [[2]]?或至少我该如何放置一个条件，该条件仅带给我属于rootNode [[1]]的值?

How can create a variable indicating that three first values belong to rootNode[[1]] and the other two to rootNode[[2]]? or at least how can I put a conditional that just bring me the values that belong to rootNode[[1]]?

推荐答案

这可能不是最优雅的解决方案，但这是我在遇到非常相似的问题后才想到的唯一解决方案.

This might not be the most elegant solution, but it's the only one I could come up with after struggling with a very similar problem.

这是一种将来自每个pdv节点的id作为属性添加到每个prix子节点的方法:

Here is a way to add the id from each pdv node as an attribute to each prix sub-node:

for (i in 1:xmlSize(rootNode)) {                

     id = xmlGetAttr(node = rootNode[[i]],    
                     name = "id")                 

     sapply(X = rootNode[[i]]["prix"],          
           fun = addAttributes,                   
           id = id)                                
 }

根据您的需要，您可以轻松地创建一个与以下两个值匹配的数据框:

Depending on your needs, you could then easily create a data frame that matches these two values:

data.frame (id     =  xpathSApply(rootNode, "//prix", xmlGetAttr, "id" ), 
            valeur =  xpathSApply(rootNode, "//prix", xmlGetAttr, "valeur")
)

返回:

       id valeur
1 1000001   1304
2 1000001   1285
3 1000001    999
4 1000002    995
5 1000002    977

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