使用 LXML 和 XPath 搜索 XML 表

Question

试图找到在Python中导航XML文件的更好方法。目前有这样的东西。

import xml.etree.ElementTree as ET
tree = ET.parse('file.xml')
root = tree.getroot()
TagSlug = '{http://www.aec.gov.au/xml/schema/mediafeed}'
for child in root:
DID = child.find('PollingDistrictIdentifier')
for grandchild in child.getchildren():
Name = grandchild.find('TagSlug+Name')
for grandgrandchild in grandchild.getchildren():
for grandgrandgrandchild in grandgrandchild.getchildren():    
PP = grandgrandchild.find(TagSlug+'PollingPlaceIdentifier')
print(PP.attrib['Id'], PP.attrib['Name'], DID.attrib['Id'], Name.text)

XML的结构与下面类似。

<PollingDistrictList Created="2018-10-30T12:01:21.043" xmlns="http://www.aec.gov.au/xml/schema/mediafeed" xmlns:eml="urn:oasis:names:tc:evs:schema:eml" xmlns:ds="http://www.w3.org/2000/09/xmldsig#" xmlns:xal="urn:oasis:names:tc:ciq:xsdschema:xAL:2.0" xmlns:xnl="urn:oasis:names:tc:ciq:xsdschema:xNL:2.0" xmlns:ts="urn:oasis:names:tc:evs:schema:eml:ts" xmlns:xs="http://www.w3.org/2001/XMLSchema-instance">
<TransactionId>4C59F7F3-2405-4443-8A1F-3F2BEF6E07C4</TransactionId>
<eml:EventIdentifier Id="12122">
<eml:EventName>State Election 2018</eml:EventName>
</eml:EventIdentifier>
<PollingDistrict>
<PollingDistrictIdentifier Id="10153">
<Name>Albert Park District</Name>
</PollingDistrictIdentifier>
<PollingPlaces>
<PollingPlace>
<PollingPlaceIdentifier Id="13133" Name="Bridport" />
<WheelchairAccess>None</WheelchairAccess>
</PollingPlace>
<PollingPlace>
<PollingPlaceIdentifier Id="13987" Name="Kerferd South" />
<WheelchairAccess>None</WheelchairAccess>
</PollingPlace>
<PollingPlaceIdentifier Id="13504" Name="Middle Park" />
<WheelchairAccess>None</WheelchairAccess>
</PollingPlace>
</PollingDistrict>
<PollingDistrict>
<PollingDistrictIdentifier = ....
et cetera

我正试图打印一份投票站ID、投票站名称、地区ID和地区名称的列表，但最后一部分很难打印。我尝试了几种不同的方法，这是其中的一些方法：

a = tree.findall('./PollingDistrictList/PollingDistrict/PollingPlaces/PollingPlace')
print(a.text)

a = tree.findall('.//PollingPlace')
print(a.text)

我最终得到的错误是"Nonetype"或"list"没有属性"text"，如果我删除了".text"，我将一无所获。我正在寻找一种更好的方法来导航XML文件，而不是做这种递归的"根目录中的子目录"的事情。

理想情况下，我会得到：

[PP1Id], [PP1Name], [District1Id], [District1Name]
[PP2Id], [PP2Name], [District1Id], [District1Name]
...
[PP1Id], [PP1Name], [District2Id], [District2Name]
etc

如有任何建议，我们将不胜感激。

Answer 1

用以下内容修复了此问题。注释，这样你就可以看到它在做什么。

import os ###Required to change directory
os.chdir('C:/XMLDataLocation') ###Set directory
import lxml
from lxml import etree
import xml.etree.ElementTree as ET ###Will parse xml
import requests ###Requests will be used for the VEC site, not utilised at this stage
tree = ET.parse('State2018MediaFilePollingLocations.xml') ###Loads file
root = tree.getroot()

TagSlug = '{http://www.aec.gov.au/xml/schema/mediafeed}' #This is pre-appended all nodes so saves space
PollingDistricts = root.findall(TagSlug+'PollingDistrict') #Goes from level 0 (root) to level 1 (PollingDistrict)
for PollingDistrict in PollingDistricts: #Required otherwise only the first district would display
DistrictID = PollingDistrict.find(TagSlug+'PollingDistrictIdentifier') #Finds the district ID
Name = DistrictID.find(TagSlug+'Name') #Finds the name of each electorate (as a child of DistrictID)
PollingPlaces = PollingDistrict.find(TagSlug+'PollingPlaces') 
PollingPlace = PollingPlaces.find(TagSlug+'PollingPlace') #These two lines are ONLY for navigating the XML file
for PollingPlace in PollingPlaces: #Required otherwise it would only print the first booth in each electorate
PPID = PollingPlace.find(TagSlug+'PollingPlaceIdentifier') #Finds both the booth ID and name
print(PPID.attrib['Id'], PPID.attrib['Name'], DistrictID.attrib['Id'], Name.text) #Prints the text