如何处理具有相同标签的 XML 元素迭代嵌套属性

如何解决如何处理具有相同标签的 XML 元素迭代嵌套属性

我正在尝试解析 NPORT-P XML SEC 提交。我的代码（Python 3.6.8）带有示例 XML 记录：

import xml.etree.ElementTree as ET
content_xml = '<?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/nport" xmlns:com="http://www.sec.gov/edgar/common" xmlns:ncom="http://www.sec.gov/edgar/nportcommon" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><headerData></headerData><formData><genInfo></genInfo><fundInfo></fundInfo><invstOrSecs><invstOrSec><name>N/A</name><lei>N/A</lei><title>US 10YR NOTE (CBT)Sep20</title><cusip>N/A</cusip>        <identifiers>          <ticker value="TYU0"/>        </identifiers>        <derivativeInfo>          <futrDeriv derivCat="FUT">            <counterparties>              <counterpartyName>Chicago Board of Trade</counterpartyName>              <counterpartyLei>549300EX04Q2QBFQTQ27</counterpartyLei>            </counterparties><payOffProf>Short</payOffProf>            <descRefInstrmnt>              <otherRefInst>                <issuerName>U.S. Treasury 10 Year Notes</issuerName>                <issueTitle>U.S. Treasury 10 Year Notes</issueTitle>                <identifiers>                  <cusip value="N/A"/><other otherDesc="USER DEFINED" value="TY_Comdty"/>                </identifiers>              </otherRefInst>            </descRefInstrmnt>            <expDate>2020-09-21</expDate>            <notionalAmt>-2770555</notionalAmt>            <curCd>USD</curCd>            <unrealizedAppr>-12882.5</unrealizedAppr></futrDeriv>        </derivativeInfo>      </invstOrSec>    </invstOrSecs>    <signature>    </signature>  </formData></edgarSubmission>'
content_tree = ET.ElementTree(ET.fromstring(bytes(content_xml,encoding='utf-8')))
content_root = content_tree.getroot()
for edgar_submission in content_root.iter('{http://www.sec.gov/edgar/nport}edgarSubmission'):

    for form_data in edgar_submission.iter('{http://www.sec.gov/edgar/nport}formData'):

        for genInfo in form_data.iter('{http://www.sec.gov/edgar/nport}genInfo'):
            None
        for fundInfo in form_data.iter('{http://www.sec.gov/edgar/nport}fundInfo'):
            None            
        for invstOrSecs in form_data.iter('{http://www.sec.gov/edgar/nport}invstOrSecs'):

            for invstOrSec in invstOrSecs.iter('{http://www.sec.gov/edgar/nport}invstOrSec'):

                myrow = []
                myrow.append(getattr(invstOrSec.find('{http://www.sec.gov/edgar/nport}name'),'text',''))
                myrow.append(getattr(invstOrSec.find('{http://www.sec.gov/edgar/nport}lei'),''))
                security_title = getattr(invstOrSec.find('{http://www.sec.gov/edgar/nport}title'),'')
                myrow.append(security_title)
                myrow.append(getattr(invstOrSec.find('{http://www.sec.gov/edgar/nport}cusip'),''))

                for identifiers in invstOrSec.iter('{http://www.sec.gov/edgar/nport}identifiers'):

                    if identifiers.find('{http://www.sec.gov/edgar/nport}isin') is not None:
                        myrow.append(identifiers.find('{http://www.sec.gov/edgar/nport}isin').attrib['value'])
                    else:
                        myrow.append('')
                        if security_title == "US 10YR NOTE (CBT)Sep20":
                            print("No ISIN")

                    if identifiers.find('{http://www.sec.gov/edgar/nport}ticker') is not None:
                        myrow.append(identifiers.find('{http://www.sec.gov/edgar/nport}ticker').attrib['value'])
                    else:
                        myrow.append('')
                        if security_title == "US 10YR NOTE (CBT)Sep20":
                            print("No Ticker")

                    if identifiers.find('{http://www.sec.gov/edgar/nport}other') is not None:
                        myrow.append(identifiers.find('{http://www.sec.gov/edgar/nport}other').attrib['value'])
                    else:
                        myrow.append('')
                        if security_title == "US 10YR NOTE (CBT)Sep20":
                            print("No Other")   

这段代码的输出是：

No ISIN
No Other
No ISIN
No Ticker

这个工作正常，除了标识符 iter invstOrSec.iter('{http://www.sec.gov/edgar/nport}identifiers') 在 formData>invstOrSecs>invstOrSec 下找到标识符，但也在下面的其他标识符formData>invstOrSecs>invstOrSec>derivativeInfo>futrDeriv>descRefInstrmnt>otherRefInst 下的嵌套标签。如何将我的迭代器或查找限制在正确的级别？我没有成功地尝试获取父级，但我没有找到如何使用 {namespace} 标记符号来做到这一点。有什么想法吗？

解决方法

所以我使用这样的导入从 ElementTree 切换到 lxml 以避免代码更改：

from lxml import etree as ET

确保选中 https://lxml.de/1.3/compatibility.html 以避免兼容性问题。在我的情况下，lxml 工作没有问题。

然后我就可以使用 getparent() 方法来只从 XML 文件的右侧部分读取标识符：

if identifiers.getparent().tag == '{http://www.sec.gov/edgar/nport}invstOrSec':