Question

我有XML文件，由37个主要文件夹组成，每个主要文件夹都有次要文件夹，每个次要文件夹有3个地标。

我想将此节点添加到第一个主文件夹中第一个小文件夹的第一个地标。

我试图这样做，但有些问题面临着我...... 首先是我要添加的节点

top = newXMLNode("description")

table = newXMLNode("table", attrs = c(width = 300, border = 1), parent = top)
tbody <- newXMLNode("tbody",parent = table)
tr <- newXMLNode("tr",parent = tbody)
th <- newXMLNode("th",attrs = c(scope = "col"),scope1 = 5,parent = tr)
th <- newXMLNode("th",attrs = c(scope = "col"),scope1 = "MD",parent = tr)
th <- newXMLNode("th",attrs = c(scope = "col"),scope1 = "PM",parent = tr)
tr <- newXMLNode("tr",parent = tbody)

th <- newXMLNode("th",attrs = c(scope = "col"),scope1 = 5,parent = tr)
th <- newXMLNode("th",attrs = c(scope = "col"),scope1 = "MD",parent = tr)
th <- newXMLNode("th",attrs = c(scope = "col"),scope1 = "PM",parent = tr)
tr <- newXMLNode("tr",parent = tbody)
th <- newXMLNode("th",attrs = c(scope = "col"),scope1 =5,parent = tr)
th <- newXMLNode("th",attrs = c(scope = "col"),scope1 = "MD",parent = tr)
th <- newXMLNode("th",attrs = c(scope = "col"),scope1 = "PM",parent = tr)
tbody <- newXMLNode("tbody",parent = table)

th <- newXMLNode("img",attrs = c(src = URL,width = "700",height= "777",alt=""),parent =top )

这是我试过的......

data <- xmlTreeParse("xml_data.xml")
data$doc$children$Folder[[4]][[3]][[3]]$description <- top 
saveXML(data, file ="xml_data.xml")

第一个问题是：当我在控制台中写“data$doc$children$Folder[[4]][[3]][[3]]”时，描述节点没有出现在控制台中，当我写“data$doc$children$Folder[[4]][[3]][[3]]$description”它出现时我不知道为什么会发生这种情况..

第二个问题是：当我使用saveXML来检查描述是否在第一位标记时......出现此错误..

Error in (function (classes, fdef, mtable)  : 
  unable to find an inherited method for function ‘saveXML’ for signature ‘"XMLDocument"’

我搜索了这个，我发现我应该使用data <- xmlTreeParse(Url,useInternalNodes = TRUE ) ....但这不允许我使用data$doc$children$Folder[[4]][[3]][[3]] ......

那么请问，有没有办法将节点添加到xml文件中的这个位置？或者我的问题有解决方案吗？

here's我的xml文件。

Answer 1

考虑使用getNodeSet查找要添加XML片段的特定元素，然后在定义新子元素时确保将新元素的父元素引用到此节点集：

data <- xmlTreeParse("xml_data.xml")
firstplacemark <- getNodeSet(data, "/Folder/Folder[1]/Folder[1]/Placemark")

top <- newXMLNode("description", parent = firstplacemark) 

#... same code as above 


saveXML(data, file="xml_data.xml")

输出

<?xml version="1.0"?>
<Folder>
  <name>All Maps</name>
  <visibility>0</visibility>
  <Folder>
    <name>Kornich ElNile</name>
     <visibility>0</visibility>
     <Folder>
       <name>Kornich ElNile;Zera3y To Arcadia</name>
       <visibility>0</visibility>
       <Placemark>
         <name>Directions from 30.10093 31.2401 to 30.07046 31.22686</name>
         <visibility>0</visibility>
         <styleUrl>#msn_ylw-pushpin0</styleUrl>
         <LineString>
           <tessellate>1</tessellate>
           <coordinates>
                31.23924,30.09923,0 31.23904,30.09886,0
                31.23859,30.09802,0 31.23836,30.09758,0 31.23813,30.09719,0 
                31.23796000000001,30.09691,0 31.23781,30.09663,0 31.23747,30.09608,0 
                31.2371,30.09546,0 31.2351,30.09159,0 31.23495,30.09131,0 
                31.23487,30.09118,0 31.2347,30.09093,0 31.23448,30.09059,0 
                31.23437,30.09043,0 31.23428,30.09029,0 31.23422,30.09021,0 
                31.23415,30.0901,0 31.23406,30.08992,0 31.23397,30.08968,0 
                31.23387,30.08943,0 31.23373,30.08903,0 31.23359,30.08863,0 
                31.2335,30.08835,0 31.23344,30.08804,0 31.23338,30.08776,0 
                31.23332,30.08751,0 31.23321,30.08723,0 31.23313,30.08706,0 
                31.23306,30.0869,0 31.23295,30.08667,0 31.23293,30.08662,0 
                31.23281,30.08629,0 31.23273,30.08606,0 31.23272,30.086,0 
                31.23266,30.08576,0 31.23259,30.08551,0 31.23245,30.08498,0 
                31.23235,30.08466,0 31.23223,30.08428,0 31.23205,30.08388,0 
                31.23181,30.08342,0 31.23176,30.08333,0 31.23143,30.08276,0 
                31.23135,30.08261,0 31.23119,30.08228,0 31.23109,30.08202,0 
                31.23096,30.08167,0 31.2309,30.08148,0 31.23084,30.08124000000001,0 
                31.2308,30.08102,0 31.23078,30.08076,0 31.23077,30.08049000000001,0 
                31.23076,30.0803,0 31.23073,30.08011,0 31.23068,30.07991,0 
                31.23064,30.07979,0 31.23055,30.07957,0 31.23032,30.07908,0 
                31.23007,30.07857,0 31.23005,30.07854,0 31.22974,30.07796,0 
                31.22963,30.07776,0 31.22945,30.07743,0 31.22907,30.07672,0 
                31.22897,30.07651,0 31.22842,30.07561,0 31.22790000000001,30.07482,0 
                31.22782,30.07468,0 31.22758,30.07423,0 31.22754000000001,30.07415,0 
                31.22754000000001,30.07414,0 31.22751,30.07409,0 31.22744,30.0739,0 
                31.22738,30.07369,0 31.22735,30.07353,0 31.22735,30.07347,0 
                31.22731,30.07324,0 31.22729,30.073,0 31.22727,30.07256,0 
                31.22724,30.07227,0 31.22712,30.07166,0 31.22703,30.07125,0 
                31.22697000000001,30.07097,0                    
           </coordinates>
        </LineString>
        <description>
          <table width="300" border="1">
            <tbody>
              <tr>
                <th scope="col">5</th>
                <th scope="col">MD</th>
                <th scope="col">PM</th>
              </tr>
              <tr>
                <th scope="col">5</th>
                <th scope="col">MD</th>
                <th scope="col">PM</th>
              </tr>
              <tr>
                <th scope="col">5</th>
                <th scope="col">MD</th>
                <th scope="col">PM</th>
              </tr>
            </tbody>
            <tbody/>
          </table>
          <img src="http://www.example.com" width="700" height="777" alt=""/>
        </description>
      </Placemark>
 ...

将节点插入XML文件中的某个节点使用R.

1 个答案: