Selecting specific XML nodes in R?

Question

I am using XML package in R to parse a XML file that has the following structure.

 <document id="Something" origId="Text">
    <sentence id="Something" origId="thisorig" text="Blah Blah.">
    <special id="id.s0.i0" origId="1" e1="en1" e2="en2" type="" directed="True"/>
    </sentence>
     <sentence id="Something" origId="thisorig" text="Blah Blah.">
      </sentence>
</document>

I want to select the nodes having </special> tag in them in one variable and the nodes without the </special> tag in other variable.

Is it possible to do it with R any pointers/answers will be very helpful.

http://stackoverflow.com/questions/1395528/scraping-html-tables-into-r-data-frames-using-the-xml-package — Chase, Apr 07 '11 at 21:01
@Chase: No this is not I am looking for, still stuck with the problem. — Shreyas Karnik, Apr 08 '11 at 04:35

Dieter Menne · Accepted Answer · 2011-04-08T10:21:13.270

I added a few more cases to test for exceptions:

<document id="Something" origId="Text">
    <sentence id="Something" origId="thisorig" text="Blah Blah.">
    <special id="id.s0.i0" origId="1" e1="en1" e2="en2" type="" directed="True"/>
    </sentence>
    <sentence id="Else" origId="thatorig" text="Blu Blu.">
      <special id="id.s0.i1" origId="1" e1="en1" e2="en2" type="" directed="True"/>
    </sentence>
     <sentence id="Something" origId="thisorig" text="Blah Blah.">
       <notso id = "hallo" />
      </sentence>
     <sentence id="Something no sentence" origId="thisOther" text="Blah Blah.">
      </sentence>
</document>

library(XML)
doc = xmlInternalTreeParse("sentence.xml")
hasSentence = xpathApply(doc, "//sentence/special/..")
xpathApply(doc, "/document/sentence[not(child::special)]")

score 2 · Answer 2 · answered Apr 08 '11 at 10:35

2

Parse the xml tree, use xpath to specify the location of the nodes.

doc <- xmlTreeParse("test.xml", useInternalNodes = TRUE)
special_nodes <- getNodeSet(doc, "/document//special")

answered Apr 08 '11 at 10:35

Richie Cotton

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How would he get the non-special nodes with this approach? – Scott C Wilson Jan 17 '15 at 19:24

Selecting specific XML nodes in R?

2 Answers2