Question

我有这个html文件

<html>

<table width="111" >

  <tr>  <td> A </td>
        <td> B </td>
  </tr>
  <tr>  <td> C </td>
        <td> D </td>
  </tr>

</table> 

<table width="222" >

  <tr>  <td> E </td>
        <td> F </td>
  </tr>
  <tr>  <td> G </td>
        <td> H </td>
  </tr>

</table> 
</html>

我在R正在做

library(XML)
tree = htmlTreeParse(file, useInternal=TRUE, asTree=TRUE)
table = getNodeSet(tree, "//table[@width='222']")[[1]]
xpathSApply(table, "//td", xmlValue)

我正在

[1] " A " " B " " C " " D " " E " " F " " G " " H "

而我却跳来跳去

[1]  " E " " F " " G " " H "

我无法理解发生了什么

Answer 1

就这样做：

# Load libraries
library(XML)

# Load data
base_html <- "<html><table width='111'><tr><td>A</td><td>B</td></tr><tr><td>C</td><td>D</td></tr></table><table width='222'><tr><td>E</td><td>F</td></tr><tr><td>G</td><td>H</td></tr></table></html>"

# Parse HTML
tree  <-  htmlTreeParse(base_html, useInternal=TRUE, asTree=TRUE)

# Get data
xpathSApply(tree, "//table[@width='222']/tr/td", xmlValue)

Answer 2

使用您当前的方法，您可以使用此方法获取值。顺便说一句，您可能不希望将名称table分配给任何内容，因为它是一个基本的R函数，可能会导致问题。也不需要Rcurl。

> library(XML)
> doc <- '<html>
  <table width="111" >
    <tr>  <td> A </td>
          <td> B </td>
    </tr>
    <tr>  <td> C </td>
          <td> D </td>
    </tr>
  </table> 
  <table width="222" >
    <tr>  <td> E </td>
          <td> F </td>
    </tr>
    <tr>  <td> G </td>
          <td> H </td>
    </tr>
  </table> 
  </html>'
> tree <- htmlTreeParse(doc, useInternal = TRUE, asTree = TRUE)
> tab <- getNodeSet(tree, "//table[@ width='222']")[[1]]
> xpathSApply(tab, "//table[@width='222']/tr/td", xmlValue)
[1] " E " " F " " G " " H "

或者，您可以

> tab2 <- getNodeSet(tree, "//table")[[2]]
> xpathSApply(tab2, "//table[@width='222']/tr/td", xmlValue)
[1] " E " " F " " G " " H "

用R刮擦

2 个答案: