将自然语言语料库的R-XML转换为数据框架

我正在使用XML包处理R中的XML文件。我的最终目标是创建一个包含以下信息的数据框架

LUWPOS LUWDictionaryForm LUWLemma OrthographicTranscription PhoneticTranscription PlainOrthographicTranscription Devoiced MoraID　ToneClass MoraID
動詞 ダイスル 題する 題し ダイシ 題し 1 3 accent 1

LUWPOS、LUWDictionaryForm、LUWLemma是LUW节点的ATT。正字法，拼音法，正字法都是在SUW，LUW的女儿。Devoiced位于电话节点中，是SUW的后代。MoraID是Mora节点的att，它是Phone的祖母。ToneClass是节点XJToBILabelTone的一个属性，它是Phone的后代。第二个冰碛是XJToBILabelTone最接近的祖先，包含音调等级=重音。 甚至不是所有的电话节点都包含att。在这种情况下，我不需要第一个MoraID。当XJToBILabelTone不包含ToneClass=“accent”时，我也不需要第二个MoraID

到目前为止，我可以做到以下几点：

doc= xmlInternalTreeParse(file="A01F0122.xml") #opens the file
    luw <- xpathSApply(doc, "//LUW", xmlAttrs) #extracts the attributes of the node LUW
    df <- data.frame(Reduce(rbind, luw)) #creates the dataframe

它包含了我想要的一些信息，但我不知道如何获得LUW的后代

<?xml version="1.0" encoding="UTF-8"?>
<Talk TalkID="A01F0122" SpeakerID="463" SpeakerBirthPlace="神奈川県" SpeakerBirthGeneration="70to74" SpeakerSex="女">
  <TalkComment>
    <Comment CommentStrings="講演ID:A01F0122"/>
    <Comment CommentStrings=""/>
    <Comment CommentStrings=""/>
  </TalkComment>
  <IPU IPUID="0001" IPUStartTime="00000.312" IPUEndTime="00001.973" Channel="L">
    <LUW LUWID="9" LUWPOS="動詞" IsNewLine="1" LineID="006" LUWDictionaryForm="ダイスル" LUWLemma="題する" LUWConjugateType="サ行変格" LUWConjugateForm="連用形">
      <SUW SUWID="1" ColumnID="001" SUWDictionaryForm="ダイスル" SUWLemma="題する" SUWConjugateForm="連用形" SUWConjugateType="サ行変格" SUWConjugateForm2="連用形" SUWConjugateType2="サ行変格" SUWPOS="動詞" OrthographicTranscription="題し" PhoneticTranscription="ダイシ" PlainOrthographicTranscription="題し" APID="7" Dep_BunsetsuUnitID="6" Dep_ModifieeBunsetsuUnitID="7">
        <TransSUW TransSUWID="1">
          <Mora MoraEntity="ダ" MoraID="1" PerceivedAcc="1">
            <Phoneme PhonemeEntity="d" PhonemeID="1">
              <Phone PhoneID="1" PhoneEntity="SclS" PhoneClass="others" PhoneStartTime="6.188682" PhoneEndTime="6.19458"/>
              <Phone PhoneID="2" PhoneEntity="d" PhoneClass="consonant" PhoneStartTime="6.19458" PhoneEndTime="6.207031"/>
            </Phoneme>
            <Phoneme PhonemeEntity="a" PhonemeID="2">
              <Phone PhoneID="1" PhoneEntity="a" PhoneClass="vowel" PhoneStartTime="6.207031" PhoneEndTime="6.317124">
                <XJToBILabelTone Time="6.212447" F0="209.865" ToneClass="IBT">%L</XJToBILabelTone>
                <XJToBILabelTone Time="6.275146" F0="195.496" ToneClass="accent">A</XJToBILabelTone>
              </Phone>
            </Phoneme>
          </Mora>
          <Mora MoraEntity="イ" MoraID="2">
            <Phoneme PhonemeEntity="i" PhonemeID="1">
              <Phone PhoneID="1" PhoneEntity="i" PhoneClass="vowel" PhoneStartTime="6.317124" PhoneEndTime="6.361029"/>
            </Phoneme>
          </Mora>
          <Mora MoraEntity="シ" MoraID="3">
            <Phoneme PhonemeEntity="sj" PhonemeID="1">
              <Phone PhoneID="1" PhoneEntity="sj" PhoneClass="consonant" PhoneStartTime="6.361029" PhoneEndTime="6.406245" EndTimeUncertain="1"/>
            </Phoneme>
            <Phoneme PhonemeEntity="i" PhonemeID="2">
              <Phone PhoneID="1" PhoneEntity="i" PhoneClass="vowel" Devoiced="1" PhoneStartTime="6.406245" PhoneEndTime="6.451461" StartTimeUncertain="1">
                <XJToBILabelWord Time="6.451461" PerceivedAccPos="1">daisji</XJToBILabelWord>
                <XJToBILabelBreak Time="6.451461">1</XJToBILabelBreak>
              </Phone>
            </Phoneme>
          </Mora>
        </TransSUW>
      </SUW>
    </LUW>
    <LUW LUWID="10" LUWPOS="助詞" IsNewLine="0" LineID="006" LUWDictionaryForm="テ" LUWLemma="て" LUWMiscPOSInfo1="接続助詞">
      <SUW SUWID="1" ColumnID="005" SUWDictionaryForm="テ" SUWLemma="て" SUWMiscPOSInfo1="接続助詞" SUWPOS="助詞" OrthographicTranscription="て" PhoneticTranscription="テ" PlainOrthographicTranscription="て" APID="7">
        <TransSUW TransSUWID="1">
          <Mora MoraEntity="テ" MoraID="1">
            <Phoneme PhonemeEntity="t" PhonemeID="1">
              <Phone PhoneID="1" PhoneEntity="SclS" PhoneClass="others" PhoneStartTime="6.451461" PhoneEndTime="6.484228">
                <XJToBILabelTone Time="6.451887" ToneClass="LTBPM" F0Uncertain="1">L%</XJToBILabelTone>
              </Phone>
              <Phone PhoneID="2" PhoneEntity="t" PhoneClass="consonant" PhoneStartTime="6.484228" PhoneEndTime="6.497334"/>
            </Phoneme>
            <Phoneme PhonemeEntity="e" PhonemeID="2">
              <Phone PhoneID="1" PhoneEntity="e" PhoneClass="vowel" PhoneStartTime="6.497334" PhoneEndTime="6.565485">
                <XJToBILabelTone Time="6.536170" F0="245.046" ToneClass="Pointer">pH</XJToBILabelTone>
                <XJToBILabelWord Time="6.565485" PerceivedAccPos="0">te</XJToBILabelWord>
                <XJToBILabelBreak Time="6.565485">1</XJToBILabelBreak>
              </Phone>
            </Phoneme>
          </Mora>
        </TransSUW>
      </SUW>
    </LUW>
  </IPU>
</Talk>

%L
A.
大寺
1.
L%
酸碱度
te
1.

（这不是一个解决方案，但对一种继续操作的方法提供了一些指导。在SO中，将代码粘贴到注释中并不是最佳选择）

应考虑列表操作路径与XML路径路由。

# get the XML doc as a list of nested lists
doc.list <- xmlToList(doc)
# inspect it
str(doc.list)

# get the LUW nested list to make it easier to process
luw.list <- dl$IPU$LUW
# inspect it
str(luw.list)

# look at the attributes
str(luw.list$.attrs)

# inspect the SUM node
str(luw.list$SUW)

#以嵌套列表的形式获取XML文档
文件清单
# get the XML doc as a list of nested lists
doc.list <- xmlToList(doc)
# inspect it
str(doc.list)

# get the LUW nested list to make it easier to process
luw.list <- dl$IPU$LUW
# inspect it
str(luw.list)

# look at the attributes
str(luw.list$.attrs)

# inspect the SUM node
str(luw.list$SUW)