为什么 if 语句在 ElementTree 解析中不起作用？

Question

我正在尝试xml使用ElementTree如下所示的文件来解析文件：

<Game>
  <Event timestamp="2016-08-14T14:23:33.634" id="1713385925" 
         version="1471181110290" last_modified="2016-08-14T14:25:11" y="11.0" 
         x="89.7" outcome="0" team_id="148" player_id="51327" sec="8" min="23" 
         period_id="1" type_id="4" event_id="205">

    <Q id="733814222" qualifier_id="265"/>
    <Q id="481660420" qualifier_id="286"/>
    <Q id="813378778" qualifier_id="152"/>
    <Q id="570443899" qualifier_id="56" value="Right"/>
    <Q id="420312891" qualifier_id="233" value="248"/>
    <Q id="1186861264" qualifier_id="13"/>
  </Event>

  <Event timestamp="2016-08-14T14:23:33.634" id="1635888622" 
         version="1471181110289" last_modified="2016-08-14T14:25:11" y="89.0" 
         x="10.3" outcome="1" team_id="143" player_id="169007" sec="8" min="23" 
         period_id="1" type_id="4" event_id="248">

    <Q id="1871787686" qualifier_id="56" value="Back"/>
    <Q id="176295814" qualifier_id="13"/>
    <Q id="69346842" qualifier_id="233" value="205"/>
    <Q id="1588029344" qualifier_id="265"/>
    <Q id="559785299" qualifier_id="285"/>
    <Q id="380723313" qualifier_id="152"/>
  </Event>
</Game>

我使用的代码很简单并且按预期工作。但是，当我尝试if condition在代码中添加时，一切都会改变

import xml.etree.ElementTree as ET

root = ET.parse(r'C:\Users\ADMIN\Desktop\Abhishek\PSG - Copy\Sample.xml').getroot()

Games = root.getchildren()
for Game in Games:
    Events = Game.getchildren()
    for Event in Events:
        type_id = Event.attrib["type_id"]
        team_id = Event.attrib["team_id"]
        Qualifiers = Event.getchildren()
        for Qualifier in Qualifiers:
            id_ = Qualifier.attrib['id']
            if id_ == 142:
                print ("val")

这是它产生的错误：

Warning (from warnings module):
  File "C:\Users\ADMIN\AppData\Local\Programs\Python\Python37\PSGPossessionSequences.py", line 9
    Games = root.getchildren()
DeprecationWarning: This method will be removed in future versions.  Use 'list(elem)' or iteration over elem instead.

Warning (from warnings module):
  File "C:\Users\ADMIN\AppData\Local\Programs\Python\Python37\PSGPossessionSequences.py", line 11
    Events = Game.getchildren()
DeprecationWarning: This method will be removed in future versions.  Use 'list(elem)' or iteration over elem instead.

Warning (from warnings module):
  File "C:\Users\ADMIN\AppData\Local\Programs\Python\Python37\PSGPossessionSequences.py", line 15
    Qualifiers = Event.getchildren()
DeprecationWarning: This method will be removed in future versions.  Use 'list(elem)' or iteration over elem instead.

我已经尝试删除if statement并且效果完美。但是，我确实需要设置一个条件来调用所有id_具有特定值的 s 。我已经尝试使用"142"以及142但问题仍然存在。究竟为什么会发生这种情况？

Answer 1

这是 getchildren() 方法已被弃用的警告。以下是如何在没有警告的情况下让孩子们现在

def goddamnit_what_are_my_kids_called(self, element):
    for child in list(element):
        print(child.tag)

Answer 2

您看到的错误不是错误，而是警告。您可以忽略它们，使它们静音，或者通过不使用.getchildren();来修复您的代码。您可以直接迭代每个 XML 元素：

root = ET.parse(r'C:\Users\ADMIN\Desktop\Abhishek\PSG - Copy\Sample.xml').getroot()

for Game in root:
    for Event in Game:
        # ...
        for Qualifier in Event:

该if测试不起作用，因为 XML 属性是字符串、文本，而不是整数值。测试字符串：

if id_ == "142":
    print("val")

您可能想要使用XPath 查询而不是循环遍历所有内容。ElementTree不过，Python 附带的基本实现有一点限制。如果您安装了lxml 库，您将获得更强大的实现，它的XPath 支持要优越得多：

from lxml import etree as ET

document = ET.parse(r'C:\Users\ADMIN\Desktop\Abhishek\PSG - Copy\Sample.xml')
root = document.getroot()

qualifier = root.xpath(".//Event/Q[@id='142']")[0]
event = qualifier.getparent()
type_id = event.attrib["type_id"]
team_id = event.attrib["team_id"]